M4maths Previous Puzzles

02 Aug 2012 mixture

There are 2 category of rice 1) @ 60rupee per Kg 2) @ 40 rupee per Kg.
The ratio of these 2 rices ( first taken first and second second in the ratio) for making the avg. rate of rice 55 rupee per Kg will be

OPtion

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

Solution

according to the given condition
60x+40(1-x)=55
so x=0.75
so ratio = 0.75/0.25 = 3/1

Correct Option: 4 Best Solution (20)

01 Aug 2012 quadratic equation

positive value of x satisfying
[x+{1/(x+1)}] = 181/60
will be

OPtion

1) 2.75
2) 3.5
3) 3.25
4) 4.25
5) 1.75
6) 5.25
7) 4.5
8) 2.25
9) 4.75
10) none of these

Solution

[x+{1/(x+1)}] = 181/60
implies that (x^2+x+1)/(x+1) = 181/60
so 60x^2-121x-121 = 0
on solving we get x = 11/4 and x = -11/15
so positive root = 11/4

Correct Option: 1 Best Solution (16)

31 Jul 2012 product

product of the positional number of all the letters of the word TWINKLE
will be
{for example positional number of A=1}

OPtion

1) 38252600
2) 38254000
3) 38253600
4) 36584000
5) 37689000
6) 36243600
7) 36532800
8) 37658900
9) 34564570
10) none of these

Solution

20*23*9*14*11*12*5= 38253600

Correct Option: 3 Best Solution (34)

30 Jul 2012 fruits

The cost of apple, banana and mango are 80rs/kg, 50rs/dozen and
40rs/kg.
Following are the discount schemes
1 kg mango free with 5 dozen banana
1 kg apple free with 10 kg mango
Cost of 23 kg mango, 7 kg apple and 15 dozen banana will be
[You have to choose a case with exact amount of all the fruits given above including the fruits in discount]

OPtion

1) 1650
2) 1680
3) 1750
4) 1890
5) 1950
6) 2040
7) 2090
8) 2010
9) 2130
10) none of these

Solution

total purchased fruits
20 kg mango and free 2 kg apple
5 kg apple
15 dozen banana and free 3 kg mango
total cast of purchased fruits = 20*40+5*80+15*50 = 800+400+750 = 1950
remaining fruits are free.

Correct Option: 5 Best Solution (0)

27 Jul 2012 x, y and z

If z = x^y,
then sum the 3 values of z on the basis of table given below:
x=2 and y=3
x=3 and y=2
x=4 and y=2

OPtion

1) 18
2) 21
3) 23
4) 26
5) 28
6) 30
7) 33
8) 37
9) 43
10) none of these

Solution

for x=2 and y=3, z=8
for x=3 and y=2, z=9
for x=4 and y=2, z=16
so sum of the 3 values of z=33

Correct Option: 7 Best Solution (38)

26 Jul 2012 alphabet

next letter of the sequence
A, F, O, B, S, .....
will be

OPtion

1) Z
2) X
3) J
4) D
5) U
6) N
7) W
8) L
9) S
10) None of these

Solution

A...BCDE...F 4
F...GHIJKLMN...O 8
O...PQRSTUVWXYZA...B 12
similarly other gap will be 16, 20

Correct Option: 6 Best Solution (21)

25 Jul 2012 percentage

2%of3%of4%of5%.........of10 - 1%of2%of3%of4%.............of9 will be

OPtion

1) 10!/10^6
2) 10!/10^16
3) 9*9!/10^6
4) 9*9!/10^16
5) 10!/10^15
6) 9!/10^16
7) 9!/10^6
8) 8*9!/10^6
9) 8*9!/10^16
10) none of these ! means factorial 5! = 5*4*3*2*1

Solution

2%of3%of4%of5%.........of10 - 1%of2%of3%of4%.............of9
= [2/100][3/100]........[9/100]*10 - [1/100][2/100].......[8/100]*9
= 10!/100^8 - 9!/100^8
= [10!-9!]/10^16
= [10*9!-9!]/10^16
= 9*9!/10^16

Correct Option: 4 Best Solution (20)

24 Jul 2012 cost

The cost of 8 dozen pencil and 2 dozen note book is 520 rupee. If cost of 3 pencil and 4 note book is 60 rupee, then sum of the cost of 1 pencil and 1 note book will be (in rupee)

OPtion

1) 12
2) 12.5
3) 13
4) 13.5
5) 14
6) 14.5
7) 15
8) 15.5
9) 16
10) none of these

Solution

Let cost of 1 pencil and 1 note book are x and y rupee respectively. Then according to the given condition
96x+24y=520
3x+4y=60
on solving we will get
x=80/39=2.05
and y=175/13=13.46
so sum = 2.05+13.46 = 15.51
so 8th will be the answer.

Correct Option: 8 Best Solution (40)

23 Jul 2012 sequence

next no. of the sequence
5/2, 17/4, 37/6, 65/8, 101/10, .........
will be

OPtion

1) 143/12
2) 137/12
3) 145/12
4) 149/12
5) 167/12
6) 197/12
7) 233/12
8) 235/12
9) 215/12
10) none of these

Solution

the sequence is
2+1/2
4+1/4
6+1/6
8+1/8
10+1/10
12+1/12

Correct Option: 3 Best Solution (29)

20 Jul 2012 words

Total no. of words of 5 letters formed by letters of the word BOMBAY.
[You should use only 5 letters out of 6 letters of the word BOMBAY]

OPtion

1) 60
2) 90
3) 120
4) 180
5) 240
6) 270
7) 300
8) 360
9) 450
10) none of these

Solution

1st case all the letters are different
total no. of words of this category = 5*4*3*2*1 = 120
2nd case B comes twice and 3 others
total no. of words of this category
= [(4*3*2*1)/(3*2*1)]*(5*4*3*2*1)/(2*1) = 240
so total words = 120+240 = 360

Correct Option: 8 Best Solution (1)