M4maths Previous Puzzles

26 Apr 2013 AP

If five times the fifth term of an AP is equal to 8 times the 8th term, value of 13th term is...

OPtion

1) -2
2) -1
3) 0
4) 2
5) 5
6) 10
7) 12
8) 15
9) 17
10) None of these

Solution

5(a+4d)=8(a+7d) (let a first term d common difference)
solve
a+12d=0 (i)

t13=a+12d
=0
option 3

Correct Option: 3 Best Solution (8)

25 Apr 2013 Quadratic

The sum of the reciprocals of two consecutive even numbers is 7/24. Numbers are.....

OPtion

1) 2,4
2) 4,6
3) 6,8
4) 8,10
5) 10,12
6) 12,14
7) 14,16
8) 16,18
9) 18,20
10)None of these

Solution

(1/(2x+2))+(1/2x)=7/24
solve
ans 6 and 8
option 3

Correct Option: 3 Best Solution (3)

24 Apr 2013 HCF

HCF of x^2+x-(2a+2)and bx^2+ax-12 is (x+4), Value of b is

OPtion

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

Solution

put -4 in given equations and solve
b=2
option 2

Correct Option: 2 Best Solution (3)

23 Apr 2013 Sequence

What is the next no of the following sequence
3,15,35,63,.....

OPtion

1) 72
2) 80
3) 88
4) 90
5) 99
6) 108
7) 120
8) 132
9) 144
10) None of these

Solution

Multiplication of odd first and second no sequence
1*3=3
3*5=15
5*7=35
7*9=63
9*11=99
option 5

Correct Option: 5 Best Solution (0)

19 Apr 2013 Ratio

Mukesh weight 56.7 kg. If he reduces his weight in the ratio 7:6. New weight of Mukesh is....

OPtion

1) 45.6 kg
2) 46.6 kg
3) 47.8 kg
4) 48.6 kg
5) 49.3 kg
6) 49.6 kg
7) 50.3 kg
8) 50.6 kg
9) 52.6 kg
10)None of these

Solution

Original weight = 56.7
new weight = 6*56.7/7 = 6*8.1 = 48.6 kg
optioni 4

Correct Option: 4 Best Solution (26)

18 Apr 2013 Number

How many numbers of two digits are divisible by 5...

OPtion

1) 12
2) 13
3) 14
4) 15
5) 16
6) 17
7) 18
8) 19
9) 20
10)None of these

Solution

series 10, 15 .... 90, 95
An=a+(n-1)d
n=18
option 7

Correct Option: 7 Best Solution (16)

17 Apr 2013 AP

How many terms of the series 1,4,7,11........ are needed to give the sum 715.

OPtion

1) 19
2) 20
3) 21
4) 22
5) 23
6) 24
7) 25
8) 26
9) 27
10) None of these

Solution

Sn= 715
then use AP Formula (Sn = n/2(2a+(n-1)d)
ans 22
option 4

Correct Option: 4 Best Solution (11)

16 Apr 2013 numbers

If in AP first term is 1 and the sum of first four term is one-third of of the sum of the next four term. Common difference of an AP is

OPtion

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

Solution

given a=1, S4=1/3(S8-S4)
2(2+3d)=1/3((4*(2+7d)-2*(2+3d))
solve
option 2

Correct Option: 2 Best Solution (14)

15 Apr 2013 Sequence

What is the next no of the following sequence
1, 26, 126, 351, ......

OPtion

1) 1251
2) 976
3) 927
4) 880
5) 835
6) 792
7) 751
8) 675
9) 651
10)None of these

Solution

1 = 1
1+5^2 = 26
26+10^2 = 126
126+15^2 = 351
351+20^2 = 751
option 7

Correct Option: 7 Best Solution (13)

12 Apr 2013 Similarity

If the perimeter of first triangle is 10 unit less than the double of perimeter of second triangle and the total perimeter of two triangles is 50 cm. Ratio of two corresponding side of triangles will be.... (Given Triangles are similar)

OPtion

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

Solution

Given condition
x=2y-10 (where x and y are the perimeter of triangles respectively)
x+y=50
therefore x=30, y=20
first triangle (side)/second triangle(side)=x/y
=30/20 = 3/2 = 3:2
option 3

Correct Option: 3 Best Solution (11)