M4maths Previous Puzzles

19 Nov 2021 Age

Age of X is thrice the age of Y. 3 year before age of X was 4 times that of Y. Sum of ages of X and Y in present will be

OPtion

1) 24
2) 28
3) 30
4) 32
5) 40
6) 48
7) 56
8) 36
9) 90
10) none of these

Solution

let age of x is a and y is b
now age of x is thrice age of y
a=3b;
now before three years (a-3)=4(b-3)
=>3b-3=4b-12
b=9
=>a=3*9=27
sum of ages is 27+9=36

Correct Option: 8 Best Solution (3)

18 Nov 2021 X

x % of x % of x % of x % 0f x is equal to x, so x will be
(given that x is a real number)

OPtion

1) 25
2) 50
3) 100
4) 200
5) 500
6) 800
7) 1000
8) data are insufficient to solve the problem
9) question is wrong
10) none of these

Solution

(x/100)*(x/100)*(x/100)*(x/100)*x=x
or,x^4=100000000
or,x=100

Correct Option: 3 Best Solution (2)

17 Nov 2021 Cards

In a game Romit first throws a coin. If he gets Tail then he puts 1 card from a deck of 52 cards. Find the probability to get a face card?

OPtion

P(A)= probability of getting tail : 1/2
P(B)= probability of getting a face card is : 12/52 = 3/13

so total probability P(A and B) = P(A).P(B)=
(1/2)*(3/13)= 3/26

Solution

1) 1/2
2) 1/4
3) 1/8
4) 1/26
5) 1/52
6) 3/26
7) 3/4
8) 1/10
9) incomplete data
10) none of these

Correct Option: 6 Best Solution (0)

16 Nov 2021 station

The distance between two stations is 100 km. 2 cars start from A and B at the same time and return to the original station with speed 48 km/hr and 64 km/hr. The time gap between their meeting twice will be

OPtion

1) 10/7 hr
2) 20/17 hr
3) 25/14 hr
4) 30/7 hr
5) 27/14 hr
6) 3 hr
7) 20/7 hr
8) 4 hr
9) 5 hr
10) none of these

Solution

Total distance covered between their meetings is 200 KM travelled together by 2 cars.
total combined speed = 64+48 = 112
Time take to cover 200KM with 112 KM/H speed is
200/112
=25/ 14 Hour

Correct Option: 3 Best Solution (1)

15 Nov 2021 inequalities

x+y+z=19
1 < x < 5, 4 < y <8, 10 < z < 14
How many outcomes are possible for integral values of x, y and z

OPtion

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

Solution

according to the given conditions
possible values of x, y and z are
x = 2, 3, 4
y = 5, 6, 7
z = 11, 12, 13
so possible combinations are
(2, 5, 12), (2, 6, 11), (3, 5, 11)

Correct Option: 3 Best Solution (2)

11 Nov 2021 Missing Number

Fill in the missing number
3, 15, 35, 63, 99, 143, 195, …?

OPtion

1. 240
2. 225
3. 235
4. 242
5. 255
6. 266
7. 256
8. 278
9. 245
10. None of the above

Solution

2^2 - 1 = 3
4^2 – 1 = 15
6^2 – 1 = 35
8^2 – 1 = 63
10^2 – 1 = 99
12^2 - 1 = 143
14^2 – 1 = 195
16^2 – 1 = 255

Correct Option: 5 Best Solution (1)

10 Nov 2021 Discount

Find the true discount reckoning 3% p.a. simple interest on ₹1802 due in 2 years’ time.

OPtion

1. 104
2. 108
3. 98
4. 106
5. 110
6. 120
7. 102
8. 100
9. 115
10. None of the above

Solution

T.D. = (A X R X T)/(100 + R X T)
= (1802 X 3 X 2)/(100 + 3 X 2)
= ₹102.

Correct Option: 7 Best Solution (2)

09 Nov 2021 share

Ram invests ₹46500 in 6% stock at 93 and sells the stock when its price rose to ₹95. He invests the sale proceeds in 9% stock at 95. Find out the change in Ram’s income.

OPtion

1. 1250
2. 1400
3. 4500
4. 4700
5. 1500
6. 1450
7. 4550
8. 4750
9. 1550
10. None of the above

Solution

Income from first stock = (6/93 x 46500) = 3000
We have to find the amount realized on selling this stock.
Amount realized on selling 93 stock = 95
∴ Amount realized on selling 46500 stock = 95/93 x 46500 = 475000
This amount is invested in 9% stock at 95.
∴ Income from the second stock
= (9/95 x 47500) = 4500
Hence, increase in income
= (4500 - 3000) = 1500.

Correct Option: 5 Best Solution (1)

08 Nov 2021 Percentage

What per cent of 75 Kg is 25.5 Kg?

OPtion

1. 14
2. 38
3. 42
4. 25
5. 46
6. 36
7. 34
8. 33
9. 28
10. None of the above

Solution

Let x% of 75 Kg be 25.5 Kg.
Then, X% of 75 Kg = 25.5 Kg
X / 100 × 75 = 25⋅5
X = 25.5 x 100 / 75 = 34.
Hence, 25.5 Kg is 34% of 75 Kg

Correct Option: 7 Best Solution (2)

05 Nov 2021 Revenue

The tax on a commodity is diminished by 18% and its consumption increases by 13%. Find the effect on revenue

OPtion

1. 6.25%
2. 6.5%
3. 7.2%
4. 7.34%
5. 7.50%
6. 8.25%
7. 7.75%
8. 6.75%
9. 6.80%
10. None of the above

Solution

Since tax × consumption = revenue
∴ Net% change in revenue = {x + y - (xy/100)} %
=[ -18 + 13 - {(18 x 13) / 100}]%
= -7.34%
∴ The revenue decreases by 7.34%

Correct Option: 4 Best Solution (3)