M4maths Previous Puzzles

02 Feb 2012 number

A positive number is such that,in its 4 digits, digit at thousands place is 1 more than the digit at hundreds place, digit at hundreds place is 1 more than the digit at tens place and digit at tens place is 2 more than the digit at units place. Digit at units place is not 0. On multiplying the number to 12, the 2 digits at ones and tens place are 0. The number will be

OPtion

1. 5431
2. 7653
3. 9875
4. 6542
5. 8764
6. 8753
7. 6431
8. 7643
9. data are insufficient
10. none of these

Solution

9875

Correct Option: 3 Best Solution (0)

01 Feb 2012 milk

There is 5 litre milk in a bucket. 1 litre of water is poured into this vessel, after that 1 litre mixture is removed, process is revised total 3 times. After 3 steps milk in the vessel will be

OPtion

1) 2.9 litre
2) 3.4 litre
3) 3 litre
4) 3.6 litre
5) 4 litre
6) 2 litre
7) 2.4 litre
8) 3.9 litre
9) 4.2 litre
10) none of these

Solution

after 1st step milk = 5*5/6
after 2nd step milk = 5*5/6*5/6
after 3rd step milk = 5*5/6*5/6*5/6
so total milk after 3 steps = 625/216

Correct Option: 1 Best Solution (7)

31 Jan 2012 equation

3x + 4y = 19
4x + 5y = 21
then 100x + 100y = ?

OPtion

1) 100
2) 200
3) 377
4) 400
5) 512
6) 600
7) 700
8) 800
9) 991
10) none of these

Solution

4x + 5y = 21
3x + 4y = 19
on subtracting 2nd by 1st, we get x+y = 2
so 100x + 100y = 200

Correct Option: 2 Best Solution (43)

30 Jan 2012 sequence

4, 12, 6, 18, 9, 27, .......
next number of the sequence will be

OPtion

1) 10
2) 11.5
3) 13.5
4) 15
5) 17.5
6) 20
7) 21
8) 43
9) 54
10) none of these

Solution

4 * 3 = 12
12 * 1/2 = 6
6 * 3 = 18
18 * 1/2 = 9
9 * 3 = 27
27 * 1/2 = 13.5

Correct Option: 3 Best Solution (36)

27 Jan 2012 value of y

if x + y = 1/x^2 + 1/x^3
then y(1/2) - y(1) will be
here y(n) is the value of y at x = n

OPtion

1) 2
2) 2.5
3) 3
4) 3.5
5) 4
6) 7.5
7) 9.5
8) 11.5
9) 13
10) none of these

Solution

y(1/2) = 23/2 = 11.5
y(1) = 1
so difference = 10.5

Correct Option: 10 Best Solution (21)

26 Jan 2012 ball

A ball is dropped to a surface for which coefficient of collision is .8. It means it returns to a height equal to .8^2 h after the collision, here h is he initial height of the ball. Height after 3 collisions will be. You should consider ball as a point particle.

OPtion

1) h
2) 0
3) 0.64h
4) 0.26h
5) 0.41h
6) 0.50h
7) 0.21h
8) 0.13h
9) ball will stop after 2 collision
10) none of these

Solution

after 1 collision height = 0.8^2 h = 0.64 h
after 2 collisions height = 0.8^2 0.64h = 0.4096 h
after 3 collisions height = 0.8^2 0.4096h = 0.262144h = 0.26h

Correct Option: 4 Best Solution (3)

25 Jan 2012 outcome

x + y + z = 5,
x is not equal to y, y is not equal to z and z is not equal to x,
all x, y and z are positive integers. Possible number of outcomes are

OPtion

1) 1
2) 2
3) 3
4) 4
5) 5
6) 6
7) 7
8) 8
9) 0
10) none of these

Solution

infinite outcome will come.
1,-1,5
1,-2,6
1,-3,7
1,-4,8
etc

Correct Option: 10 Best Solution (5)

24 Jan 2012 sequence

next number of the sequence 6, 26, 16, 96, 56, 376, ..... will be

OPtion

1) 216
2) 396
3) 496
4) 296
5) 286
6) 276
7) 196
8) 236
9) 316
10) none of these

Solution

sequence is +20, -10, +80, -40, +320, -160

Correct Option: 1 Best Solution (19)

23 Jan 2012 percentage

40 % of 30 + 30 % of 20 + 20 % of 10 = 60 % of x, then x will be

OPtion

1) 50/3
2) 100/3
3) 200/3
4) 500/3
5) 75/2
6) 125/2
7) 124/5
8) 100/9
9) 200/9
10) none of these

Solution

40 % of 30 + 30 % of 20 + 20 % of 10
= 12 + 6 + 2 = 20
so 20 = 0.6 x or x =200/6

Correct Option: 2 Best Solution (0)

21 Jan 2012 cost

Total cost of 8 TV set and 7 refrigerator is 1 lac rupee, whereas total cost of 10 TV set and 6 refrigerator is 1.1 lac rupee. Cost of 3 TV set and 2 refrigerator will be approximately

OPtion

1) 28000
2) 30000
3) 31000
4) 32000
5) 34000
6) 39000
7) 45000
8) 48000
9) 50000
10) none of these

Solution

according to the given conditions
8x + 7y = 100000
10x + 6y = 110000
on solving x = 85000/11, y = 60000/11
so 3x + 2y = 375000/11 = 34090.90

Correct Option: 5 Best Solution (0)