M4maths Previous Puzzles

30 Nov 2016 Compound Interest

Find compound interest on sum of Rs 640 at 50/3% per annum for 11/4 years.

OPtion

1) Rs 345
2) Rs 265
3) Rs 513
4) Rs 260
5) Rs 252
6) Rs 255
7) Rs 263.33
8) Rs 340
9) Rs 654
10)Rs 651

Solution

Reason
Amount = Rs [640*(1+50/(3*100)^2) (1+{(¾)*(50/3) / 100}]
= Rs (640 * (7/6)*(7/6)*(9/8))
= Rs 980
CI = Rs (980-640) = Rs340

Option 8)

Correct Option: 8 Best Solution (5)

G.S.Kantharao   8 years AGO

Principle = Rs.640
Rate = 50/3%
Time 11/4 =( 2+ ¾ ) years.
Amount for 2 Years = 640[1+(50/300)]^2 =871.111
Compound/simple Interest for ¾ years = (871*50*3)/(300*4) = 109 (approximately)
Total Compound Interest = 871 - 640 + 109 = 340 Hence my option is 8.

Like? Yes (4) | No   

Saurabh   8 years AGO

C.I = P*[ 1 + R ]^t - P
= [ 640 * [ 1 + ( 50/300 ) ] ^ ( 11/4 ) ] - 640
= 337.875
the nearest option is :::: 340 ----> option { 8 }

Like? Yes | No   

Pragati Rode   8 years AGO

P = 640 ,R = 50/3 % N = 11/4 = 2 3/4 years

Amount =P (1+r/100)^2 * (1 + (3/4)R/100)

put all values
we get
Amount = 640 * (1+(50/3)/100)^2 * (1+ (50/3)/100)
= 640 * (7/6)^2 * (9/8)
=640 * (49/36) * (9/8)
= 980
Compound interest = 980 -640
=340
so option 8

Like? Yes | No   

Mukund Manohar   8 years AGO

AMOUNT = 640 * (1+ 50/300)^2 * (1+ (3/4*50/3)/100)
= 640 * (7/6)^2 * (9/8)
= 640 * 49/36 * 9/8 = 20*7*7 = 980
CI = 980 - 640 = Rs 340

Like? Yes | No   

Dinesh Sharma   8 years AGO

apply formula: A = P(1 + r/100)^t and
C.I. = A - P we get nearby 340

Like? Yes | No   

29 Nov 2016 Coded language

If in coded language
OCTAVIUS = 128
SYLVANIA = 74
Then
GREGGORY = ?

OPtion

1) 265
2) 168
3) -65
4) -31
5) -98
6) 157
7) 113
8) 354
9) -54
10)None of these

Solution

A(1), B(2), C(3), D(4), E(5), F(6), G(7), H(8), I(9), J(10), K(11), L(12), M(13), N(13),
O(12), P(11), Q(10), R(9), S(8), T(7), U(6), V(5), W(4), X(3), Y(2), Z(1)
OCTAVIUS = [(12+3)*(7+1)]+[(5-9)*(6-8)] = 128
SYLVANIA = [(8+2)*(12+5)]+[(1-13)*(9-1)] = 74
Similarly
GREGGORY = [(7+9)*(5+7)]+[(7-12)*(9-2)] = 157

Option 6)

Correct Option: 6 Best Solution (0)

28 Nov 2016 Sequence

Find the missing number
38, 1368, 54758, 89, 7743, 704702, 67, 4355, ?

OPtion

1) 314685
2) 318216
3) 356523
4) 154821
5) 121562
6) 123523
7) 213451
8) 300568
9) 345435
10)453544

Solution

Reason-
The series is (38,1368,54758),(89,7743,704702),(67,4355,?)
3rd number in first bracket = (38^3)-(38*3) = 54758
2nd number in first bracket = (38^2)-(38*2)= 1368
Similarly
2nd number in third bracket = (67^3)-(67*3)= 300568

Option 8)

Correct Option: 8 Best Solution (10)

Rahul Hooda   8 years AGO

Actually the Answer is '300562'
Most likely a typo
Explanation:-
If we take the series as: a, b, c
then the 3rd term i.e. c = axb +2b +a
Here c = 67x4355 + 2x4355 + 67
= 291785 + 8710 + 67
= 300562

Like? Yes (2) | No   

P.ARUNA   8 years AGO

38*38-38*2=1368; 38*38*38-38*3=54758 similarly 67*67*67-67*3

Like? Yes (1) | No   

G.S.Kantharao   8 years AGO

38,38*36,[38*(38-1)+(38-3)]*38=38, 1368, 54758(First three)
89,89*87,[89*(89-1)+(89-3)]*89 =89, 7743, 704702 (Next three numbers),
67,67*65,[67*(67-1)+(67-3)]*67= 67,4335,300562 (It was given as 300568
Hence my choice is for 8.

Like? Yes (1) | No   

Aakash Beniwal   8 years AGO

logic
split in 3 groups (38,1368,54758),(89,7743,704702)),(67,4355,...)
second number of 1st group :-
38 * ( 38 - 2)= 1368
3rd Number of 1st group
{
add ((38-2)*2 + 1) =73 to 2nd number
i.e. 1368 + 73 = 1441
}
so 3rd number is
38 * 1441 = 54758

similarly in 3rd group
2nd number:-
67 * 65 = 4355
3rd number should be
((65*2 + 1) + 4355) * 67
=( 131+ 4355) *67
= 4486 * 67 = 300562 ...( I guess 8th option is misprint for 300568 instead of 300562)

or if I am wrong then please admin don't remove my logic from submission, Because it is also a valid reason, but correct if it is wrong.

Like? Yes (1) | No   

Mukund Manohar   8 years AGO

(38,1368,54758),(89,7743,704702),(67,4355,____)
2nd term (1368) = (38^2) - (38*2) = 1444 - 76 = 1368
3rd term (54758) = (38^3) - (38*3) = 54872 - 114 = 54758
Similarly,
2nd term = 4355 = (67^2) - (67*2) = 4489 - 134 = 4355
3rd term = (67^3) - (67*3) = 300763 - 201 = 300562

Like? Yes (1) | No   

ajeet singh   8 years AGO

38,(38×38-38×2),(38×38×38-38×3),89,(89×89-89×2),(89×89×89-89×3),67,(67×67-67×2),(67×67×67-67×3)
(67×67×67-67×3)=300562
not match any one of them. given above answer
So correct answer is 300562

Like? Yes | No   

Lenin   8 years AGO

( 38 * 38 ) - ( 2 * 38 ) = 1368
( 1368 * 38 ) + ( 2 * 1368 ) + 38 = 54758

similarly,
( 67 * 67 ) - ( 2 * 67 ) = 4355
( 67 * 4355 ) + ( 2 * 4355 ) + 67 = 300562

Like? Yes | No   

Ponni   8 years AGO

67
67^2 - (67*2)=4355
4355* (67+2) +67 = 300562

Like? Yes | No   

Saurabh   8 years AGO

the answer should be 300562 but since the nearest option was option { 8 } so i take it as the printing mistake
the reason is as follows:

the pattern we observe here is
first group the sequence in 3 elements each so that

{ 38 , 1368 , 54758 } { 89 , 7743 , 704702 } { 67 , 4355 , ? }

the first no. in each group is the key to obtain other no.(s) in that group

let first no. be x then ,
second no. = x * ( x - 2 )
and third no. = x * { second no. + ( 2 * ( x-2 ) ) + 1 }
By applying the same rule,
for first group ,
first no. = 38
second no. = 38 * ( 38 - 2 ) = 1368
third no. = 38 * { 1368 + ( 2 * ( 38 - 2 ) ) + 1 }
= 54758
for second group
first no. = 89
second no. = 89 * ( 89 - 2 ) = 7743
third no. = 89 * { 7743 + ( 2 * ( 89 - 2 )) + 1}
= 704702
similarly for the third group
first no. = 67
second no. = 67 * ( 67 - 2 ) = 4355
third no. = 67 * { 4355 + ( 2 * ( 67 - 2)) + 1}
= 300562 answer
rounded answer according to options
300568

Like? Yes | No   

Dinesh Sharma   8 years AGO

take group of 3 consecutive no.
and apply like this : a, a(a-2), a(a^3 - 3)
where 'a' is first no. of three consecutive.

e.g. take this 38, 1368, 54758
here "a" = 38
so, 38, 38(38-2), 38(38^2-3) and so on

But my point of view answer should be 300562 because when we take a=67 and apply on above formulae we get this number.

Like? Yes | No   

25 Nov 2016 Sum of present age

The ratio of present ages of Ram and Shyam is 4:3. If 10 years ago Ram was half of Shyam in age, what is the sum of their present ages?

OPtion

1) 8 Years
2) 20 Years
3) 35 Years
4) 45 Years
5) 14 Years
6) 30 Years
7) 54 Years
8) 21 Years
9) 34 Years
10)None of these

Solution

Reason -
Let the present age of Ram be 4x and Shyam be 3x
2(4x-10) = 3x-10
=> 5x = 10
=> x = 2
Sum of their present ages is 7x = 14 years.

Option 5)

Correct Option: 5 Best Solution (2)

devikumar   8 years AGO

ram present age is -R
shyam present age is_S
R/S=4/3
ten years age S-10=2(R-10)
S=6; R=8
their sum=6+8=14

Like? Yes (4) | No (3)  

Kunal nemu   8 years AGO

let, present ages of ram is 4x and shyam is 3x
10 years ago ram was 4x-10
and shyam is 3x-10
and the equation is ram=1/2 * shyam
so, 4x-10=1/2 * (3x-10)
5x=10
x=2
so present age of ram is 8 year and shyam is 6 year and sum is 14years

Like? Yes (2) | No (2)  

24 Nov 2016 Present age of Ashu

Ashu is as much younger to Sahil as he is older to Sumit. If the sum of the ages of Sahil and Sumit is 96 years what is present age of Ashu?

OPtion

1) 20 years
2) 42 years
3) 56 years
4) 48 years
5) 96 years
6) 24 years
7) 35 years
8) 45 years
9) 66 years
10)None of these

Solution

Reason-
Let Ashu = A
Sahil = B
Sumit = C
B - A = A - C
=> 2A = B+C
=> 2A = 96
=> A = 48
Therefore present age of Ashu is 48 years.
Option 4)

Correct Option: 4 Best Solution (21)

madanpal vishwakarma    8 years AGO

let assume Ashu age is x years.

and the common age difference is y .

so
sahil age = (x+ y) years
sumit age =(x-y) years

so as per question sum of sahiland sumit age is 96
(x+y) +(x-y)=96
x=96/2=48 years

so ashu age is 48 years.

Like? Yes (1) | No   

Ujjal Kundu   8 years AGO

because ashu is as much much younger to Sahil and as much older to Sumit for that the age of ashu is the average age of ther age 96/2=48

Like? Yes (1) | No   

G.S.Kantharao   8 years AGO

Let Sahil,Ashu,Sunit's ages are = a+x,a,a-x
Here Ashu is the middle one whose age is a
Given (a+x)+(a-x) =2a =96
a = 48.
Hence Ashu's age=48
Hence the right choice is 4.

Like? Yes (2) | No (1)  

Saurabh   8 years AGO

Let Sahil age be x, Ashu age be y, & Sumit age be z
then,
according to question the condition can be fitted as equations,

x - y = y - z --------->(1)
x + z = 96 --------->(2)
now in eq. (1), taking all variables to one side we get
x - y - ( y - z ) = 0
x + z - 2y = 0
x + z = 2y
using eq.(2)
96 = 2y ==> y = 96 / 2 = 48 Answer

Like? Yes (2) | No (2)  

rishabh tiwari   8 years AGO

let sumit age is 2 and anshu is 2 years older than sumit.
now sahil is 2 years older than anshu.
so now we have ages in ratio 2: 4: 6
According to the question we have let x is age of anshu so,
(2+6)x=96
x=12
and according to ratio it is 12*4=48 Answer

Like? Yes (1) | No (1)  

Satishbabu   8 years AGO

Lets say Ashu's age =a
Sahil=b,summit=c
2a=b+c
=>a=96/2=48

option: 4

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pawan   8 years AGO

age of sahil - age of ashu = age of ashu - age of sumit
age of sahil + age of sumit = 96
96-age of sumit- age of ashu = age of ashu - age of sumit
age of ashu = 48 yrs

Like? Yes | No   

Nishi   8 years AGO

Let the age of ashu be x
suppose if the diiference is 1year between sahil
then
x=sahil-1
x+1=sahil
similarly,1year differnece between sumit
then
x=sumit+1
x-1=sumit
sahil+sumit=96
(x+1)+(x-1)=96
2x=96
x=48
hence the present age of mahesh , x=48.

Like? Yes | No   

fazila Begum   8 years AGO

shahil is elder than ashu.ashu is elder than sumit.
Equation will be like this.
shahil-ashu=ashu-sumit
shahil+sumit=2ashu
ashu=shahil+sumit/2
gn:shahil+sumit=96
ashu=96/2=48yrs

Like? Yes | No   

shivam bansal   8 years AGO

let ashu age be x
sahil's age be x+y
sumit's age be x-y
A/Q. x+y+x-y=96
2x=96
x=48

Like? Yes | No   

mande mahendra reddy   8 years AGO

x-y=y-z
y=x+z/2
y=96/2
y=48
** Y=Aashu
X=Sahil
Z= Sumit

Like? Yes | No   

Lenin   8 years AGO

Lets assume Ashu's age = a,
Sahil's age = b,
Sumit's age = c.

In the problem statement it is given,
a + x = b,
a - x = c,
c + b = 96 ----> (a+x) + (a-x) = 96
2a=96
a=48.
option 4.

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SAYALI GADKARI   8 years AGO

Consider Ashu's age = x
Sahil = x + a
sumit = x -a

by the given condition : 2x = 96 , so x = 48

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Nirupama    8 years AGO

sahil= ashu+x
sumit=ashu-x
given
sahil+sumit=96
ashu+x+ashu-x=96
2(ashu)=96
ashu=48

Like? Yes | No   

Sumit Banerjee   8 years AGO

let the age of sahil be x, ashu be y and sumit be z.
given x-y = y-z. and x +z = 96. solving we get y = 48. hence age of ashu is 48.

Like? Yes | No   

divya hyndavi   8 years AGO

Let the difference of Ashu's age(A) with Sahil(Sa) and sumit(Su) be x.
A=Sa-x-----Ashu is younger to sahil
A=Su+x------Ashu is older to Sumit
add both equations 2A=Sa+Su
2A=96
A=48
So Ashus present age is 48 years

Like? Yes | No   

Vinod Kumar   8 years AGO

let age of sumit be x and ashu be y years older to him.
sumit age + sahil age = 98;
so ashu age = 98/2 = 48

Like? Yes | No   

Dinesh Sharma   8 years AGO

Sahil - Ashu = Ashu - Sumit - - - - - - (i)
Sahil + Sumit = 96 - - - - - - - - - - - - - - (ii)

On solving these two equations, we get

Ashu = 48 years

Like? Yes (1) | No (1)  

nidhi   8 years AGO

Sumit+Sahil=96 eq(1)
Ashu=sumit+x eq(2)
Sahil=Ashu+x eq(3)
From eq(2) and eq(3)
Ashu-Sahil=Sumit-Ashu
therefore, 2Ashu=Sumit+Sahil=96 yrs
so, Ashu= 96/2=48yrs

Like? Yes | No   

Ranjinii   8 years AGO

Sumit: 24 years
Ashu: 48 years
Sahil: 72 years

Sahil > Ashu > Sumit

1x + 3x = 96
x = 24 ( Sumits age )
2x = 48 ( Ashus age )
3x = 72 ( Sahils age )

24 + 72 = 96

Like? Yes | No (1)  

Devendra Marghade   8 years AGO

Let the present age of Ashu=x, Sahil=y and Sumit=z, then y-x=x-z => 2x= y+z
Also y+z=96, so 2x=96 or x=48
Option 4)

Like? Yes | No (1)  

23 Nov 2016 Ratio of volume

If the sphere is inscribed in a cube then the ratio of the volume of the cube to the volume of the sphere is:

OPtion

1) pi:2
2) pi:3
3) pi:4
4) pi:6
5) 6:pi
6) 4:pi
7) 3:pi
8) 2:pi
9) 5:pi
10)None of these

Solution

Reason -
Let the edge of the cube be a
Then the diameter of the sphere is a
Volume of cube/volume of sphere = a^3/[(4pi/3) * (a/2)^3
= 6/pi i.e. 6:pi

Option 5)

Correct Option: 5 Best Solution (0)

22 Nov 2016 Coded language

If in coded language
COLUMBUS = 130
HUMPHERY = 18
Then
JERMAINE = ?

OPtion

1) 65
2) -91
3) 25
4) -47
5) 35
6) -65
7) 27
8) -73
9) 43
10) None of these

Solution

A(1), B(2), C(3), D(4), E(5), F(6), G(7), H(8), I(9), J(10), K(11), L(12), M(13), N(14), O(15), P(16), Q(17), R(18), S(19), T(20), U(21), V(22), W(23), X(24), Y(25), Z(26)

COLUMBUS = [(3-15)*(12-21)]+[(13-2)*(21-19)]= 130
HUMPHERY = [(8-21)*(13-16)]+[(8-5)*(18-25)]= 18
Similarly
JERMAINE = [(10-5)*(18-13)]+[(1-9)*(14-5)]= -47

Option 4)

Correct Option: 4 Best Solution (0)

21 Nov 2016 Series

Find the missing number of the series
17, 16, 136, 38, 16, 418, 24, ?, 144

OPtion

1) 31
2) 68
3) 256
4) 57
5) 81
6) 45
7) 62
8) 25
9) 86
10)20

Solution

Reason-
The series is (17,16,136),(38,16,418),(24,?,144)
3rd number in first bracket = 17*(1+7)= 17*8= 136
2nd number in first bracket = [(1+7)-(1+3+6)]^4 = (8-10)^4 = 16

2nd number in third bracket = [(2+4)-(1+4+4)]^4 = (6-9)^4 = 81

Option 5)

Correct Option: 5 Best Solution (0)

18 Nov 2016 Train's Length

A train can pass a 100m long platform in 25 sec. And the same train passes a pole in 15 sec. The train’s length in meters is:

OPtion

1) 655
2) 155
3) 275
4) 375
5) 50
6) 150
7) 175
8) 200
9) 215
10)None of these

Solution

Reason-
Let the length of the train be x meters.
Then.
x/15 = (x+100)/25
=> x = 150 m.

Option 6)

Correct Option: 6 Best Solution (19)

Pragati Rode   8 years AGO

Let assume the train's length in meters is x

from first condition
speed of train = distance /time
=100+x/25
from second condition
speed of train = x/15
so we get
100+x/25 = x/15
=> 15(100+x) = 25x
1500 + 15x = 25x
10x = 1500
x= 150
so option is 6)

Like? Yes (4) | No (1)  

madanpal vishwakarma    8 years AGO

let assume that the length of the train is l meter

So to pass the platform it need to travel (l+100) meter

and to pass a pole it need to travel l meter .

So the speed to pass platform is = (l+100) meter / 25 sec
and speed to pass a pole is = l/15

so because speed is same

l/15 =(l+100)/25

after solving l=150 meter

Like? Yes (2) | No   

SATHEESH V   8 years AGO

let 'x' be the length of the train

(100+x)/25=x/15

x=150

Like? Yes (1) | No (1)  

Jagriti Priya   8 years AGO

let length of train = x m and speed = y m/sec
x/y = 15, y = x/15
(x+100)/25 = x/15
x = 150 m.

Like? Yes | No   

Lenin   8 years AGO

let the length of the train be l.
so, the train's speed is

(100 + l)/25 = l/15

--> 10 l = 1500
--> l = 150

ans is 150 m. option 6.

Like? Yes | No   

Parikshit Sen   8 years AGO

Let the length of the train be x. A.T.Q
(100+x)/25=x/15
x=150

Like? Yes | No   

Venkat   8 years AGO

(100+train length)/25 = train length/15
solve above equation
train length = 150

Like? Yes | No   

divyasree   8 years AGO

let the length of the train be x
then total of length train along with platform length be (100+x)
the length of pole be negligible so consider length of train be x
(100+x)÷25=(x÷15)
on solving we get x=150

Like? Yes | No   

nimisha gupta   8 years AGO

Speed of train while passing a platform
=(x+100)/25
Speed of train while crossing the pole
=x/15
Solving the 2 equation, we get,
(x+100)/25=x/15
15x 1500=25x
X=150 m

Like? Yes | No   

naaz   8 years AGO

train length + platform length /25= (train length/ 15)
train length = 150

Like? Yes | No   

S.Anitha   8 years AGO

let length of train be x
x+100/25=x/15
15(x+100)=25x
x=150

Like? Yes | No   

Samjukta Das   8 years AGO

Let the length of the train be x metres and its speed be y m/sec
Then , x/y=15
=x+100/25=x/15
x=150m

Like? Yes | No (1)  

Devendra Marghade   8 years AGO

Let the length of the train=x m. and speed=y m/s, then
x/y=15 —(i) and
(x+100)/y=25 —(ii)
On solving (i) & (ii), x=150, y=10
Option 6)

Like? Yes | No (1)  

chetan   8 years AGO

let train length be x.
then (100+x) / 25 = x / 15.
solving for x we get 150.
So the correct option is 6.

Like? Yes | No (1)  

pawan   8 years AGO

total distance covered by train= 100+ l
l is length of train
now speed of train in platform,=( l+100)/25
speed while crossing pole= l/15
l/15=(l+100)/25
l=150m

Like? Yes | No (1)  

DEVANSH SUBNANI   8 years AGO

25=[100+L(Train)]/Speed(Train)
Speed(Train)=[100+L(Train)]/25-----------(1)

15=L(Train)/Speed(Train)
15Speed(Train)=Length(Train)---------(2)

On solving (1) and (2)
Length of Train=150
Option 6)

Like? Yes | No (1)  

Nitish kesarwani   8 years AGO

let length of train passes part be x
now 100+X/25=X/15
X=1500/10=150
option 6

Like? Yes (1) | No (2)  

subiraj   8 years AGO

Let the length of the train be 'l' and velocity of train be 'v'
(100+l)/v=25
l/v=15
l=15v
(100+15v)/v=25
100/v=10
v=10 m/s
l=15*10
l=150m

Like? Yes | No (1)  

rajeev ranjan mishra   8 years AGO

(L+ 100)/25 =v and L/15=v
thus, solve for L
L=150

Like? Yes | No (1)  

17 Nov 2016 Original number of man

A contractor took a job for his group to do in 20 days. But 12 men did not come up for the job and job was done by remaining man in 32 days. The original number of man in contractor’s team were?

OPtion

1) 51
2) 66
3) 54
4) 32
5) 65
6) 54
7) 34
8) 36
9) 45
10)40

Solution

Reason -
Let there be x men originally.
X men do the job in 20 days
X-12 men can do the job in 20x/(x-12) days.
Therefore 20x/(x-12) = 32
=> x = 32
Option 4)

Correct Option: 4 Best Solution (9)

SARATCHANDRAN   8 years AGO

let the total number of men initially be N.so N men complete work in 20 days and therefore total work =20*N
similarly (N-12)*32=total work
so 20*N=32*(N-12)
20*N=32*N-384
12*N=384
so N=32

Like? Yes (3) | No (1)  

madanpal vishwakarma    8 years AGO

let us assume that the original number of man is x

so x man can do the job in 20 day's so the one day work of x man is = (1/20)

if 12 man din't come than the one day work by (x-12) people is
=(1/32)

x man in 20 = (x-12) man in 30 day

so

x * 20 =(x-12) *32
20x= 32x -(12*32)

32x-20x =12*32
12x= (12*32)
x=(12*32)/12 =32

So the original number of man is 32 .

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Nitish kesarwani   8 years AGO

X men in group do a work in 20 days
1 days work=20*X
X-12 finish a work in 32 days
hence
X*20= (X-12)*32
so X= 32*12/12 option 4

Like? Yes (3) | No (2)  

Amit kumar singh   8 years AGO

Let original no.=x
Then efficienby of each men=1/20x.
Now,since 12 men did not come then now no. Of men=x-12.
These men finished work in 32 days.So efficiency=1/32(x-12).
Since efficiency of each man will remain same.
So,1/20x=1/32(x-12).
Solve equation you will get x=32.

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Jagriti Priya   8 years AGO

let total men = n
remaining men = n-12
n men done work in 20 days = 20n
(n-12) remaining work completed in 32 days = (n-12)32
20n = (n-12)32
20n = 32n - 384
12n = 384
n = 32.

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DEVANSH SUBNANI   8 years AGO

Let original number of men in contractor's team be x
X:20::32:(x-12)
=>x(x-12)=20*32
=>x(x-12)=640
=>x=32
Option 4)

Like? Yes | No (1)  

Devendra Marghade   8 years AGO

Let x men can complete the work in 20 days, so total work=20x
Also x-12 men can do the same work in 32 days.
So 20x= 32(x-12)
=> 12x= 384 or x=32
Option 4)

Like? Yes | No (1)  

Pragati Rode   8 years AGO

Let the original number of man in contractor's team is x

x men will do work in 20 days
x-12 will do same work in 32 days
inversely proportion

x * 1/32 = (x-12)* 1/20
by solving we get,

20*x = 32(x-12)
12x = 384
x = 32
so option is 4

Like? Yes | No (1)  

arun   8 years AGO

20x/1=(x-12)32/1
20x=32x-384
12x=384
x=32

Like? Yes | No (1)