M4maths Previous Puzzles

28 Mar 2018 Profit and Loss

96 bananas are bought for Rs. 384 and sold at the rate of Rs. 66 per dozen. The percentage of profit or loss is:

OPtion

1) 35 % Profit
2) 34 % Profit
3) 35.5 % Profit
4) 36 % Profit
5) 37.5 % Profit
6) 37 % Profit
7) 36.5 % Profit
8) 38 % Profit
9) 38.5 % Profit
10) None of these

Solution

Cost of 1 banana= 384/96 = 4
Selling price of 1 banana = 66/12 = Rs. 5.5

As SP > CP so its profit
So Profit % = (5.5 - 4 )*100/4 = 37.5 %
Option 5)

Correct Option: 5 Best Solution (0)

27 Mar 2018 Work & Time

If 4 men and 7 women can do a piece of work in 7 days and 8 men and 12 women can do it in 4 days, how
many days will 18 men and 6 women take to do it?

OPtion

1) 4.66
2) 4.75
3) 5.33
4) 5.00
5) 4.50
6) 4.33
7) 5.66
8) 5.75
9) 4.00
10) None of these

Solution

Let a man's daily work is x units and that of a woman is y units.
So total amount of work, W = 7(4x + 7y) = 4(8x + 12y)

Solving we get,
=> 49y - 48y = 32x - 28y
=> y = 4x

Now, 4 x + 7 y can do work in 7 days.
So, 4x + 28x can do work in 7 days.
So, 32 x can do work in 7 days.

Now, 18x + 6y = 18x + 24x = 42x

Hence, if 32 x can do work in 7 days, 42x can do work in (32*7)/42 = 5.33 days.

Option 3)

Correct Option: 3 Best Solution (0)

26 Mar 2018 Age

In 2020, A would be 13 years older than B who would be seven times as old as C. Also, the total of the ages of A, B and C in 2019 would be 145 years. What is the average of A and B ages in 2022 ?

OPtion

1) 71 years
2) 70.5 years
3) 69.5 years
4) 74.5 years
5) 72.5 years
6) 75.5 years
7) 71.5 years
8) 73.5 years
9) 68.5 years
10)None of these

Solution

Total ages of A+B+C in 2019 = 145
Total ages of A+B+C in 2020 = 145 + 3 = 148 years

Let’s assume Age of B be B years
Age of A = B+13
Age of C = B/7

In 2020
Total age = B + 13 + B + B/7 = 148
Solving 15B/7 = 135
B = 63
A = B+13 = 76
C = 63/7 = 9

In 2022 - i.e. 2 years later
Age of A = 76+2 = 78
Age of B = 63+2 = 65

Average of ages = 71.5 years


Option 7)

Correct Option: 7 Best Solution (0)

23 Mar 2018 Bankers Discount

The banker's discount on a bill due 1 months hence at 26% is Rs. 1950. What is the true discount?

OPtion

1) 1901.66
2) 1904.96
3) 1906.65
4) 1908.65
5) 1947.36
6) 1857.06
7) 1909.92
8) 1907.23
9) 1911.26
10) None of these

Solution

T.D.=B.D. x 100 /(100 + (R x T))
=> 2017*100/(100+(26*1/12))
=> ~1908.65

Option 4)

Correct Option: 4 Best Solution (0)

22 Mar 2018 Stocks

Shruti invests a part of Rs. 18,000 in 10% stock at Rs. 105 and the remainder in 15% stock at Rs. 105. If her total dividend per annum is Rs. 2100, how much does she invest in 10% stock at Rs. 105?

OPtion

1) Rs. 8000
2) Rs. 8100
3) Rs. 9000
4) Rs. 8900
5) Rs. 8200
6) Rs. 8800
7) Rs. 9300
8) Rs. 9700
9) Rs. 9900
10)Rs. None of these

Solution

Let investment in 10% stock be Rs. x.
Then, investment in 15% stock = Rs. (18000 - x).
Therefore (10/105)*x + (15/105)(18000 - x) = 2100
=> 2x/21 + 1/7(18000-x) = 2100
=> -x/21 + 18000/7 = 2100
solving
=> x = 9900

Option 9)

Correct Option: 9 Best Solution (0)

21 Mar 2018 Perfect Squares

How many factors of 13699532025 are perfect squares?

OPtion

1) 12
2) 8
3) 16
4) 18
5) 25
6) 15
7) 30
8) 40
9) 24
10) None of these

Solution

13699532025 = 3^8 * 5^2 * 17^4

Any factor of this number should be of the form 3^a * 5^b * 17^c.

For the factor to be a perfect square a,b,c have to be even.

a can take values 0, 2, 4, 6, 8
b can take values 0, 2
and c can take values 0, 2, 4

Total number of perfect squares = 5 * 2 * 3 = 30

Correct Option: 7 Best Solution (0)

20 Mar 2018 Simple Interest

A sum of money at simple interest amounts to Rs. 815 in 4 years and to Rs. 854 in 8 years. The sum is:

OPtion

1) 786
2) 796
3) 726
4) 736
5) 766
6) 756
7) 746
8) 776
9) 716
10) None of these

Solution

S.I. for 4 years = Rs. (854 - 815) = Rs. 39.
S.I. for 1 year = Rs. (854 - 815) = Rs. 39/4

S.I. for 4 years = Rs. 39
Principal = Rs. (815 - 39) = Rs. 776

Correct Option: 8 Best Solution (0)

19 Mar 2018 Decode

If
12 = 61, 25 = 152 and 58 = 245
then
71 = ?

OPtion

1) 447
2) 419
3) 417
4) 427
5) 497
6) 481
7) 437
8) 457
9) 467
10) None of these

Solution

Number xy is decoded as concatenation of 3y and x => (3y)(x) = 3yx
So 71 = (3*1)(7) = 37

Option 10)

Correct Option: 10 Best Solution (0)

16 Mar 2018 Simple Interest

What would be the simple interest on a sum of Rs. 2018 for 3 years term at 14% p.a. interest rate?

OPtion

1) 2265.56
2) 2065.56
3) 2365.56
4) 2860.56
5) 2865.56
6) 2815.56
7) 0847.56
8) 2885.56
9) 2845.56
10) None of these

Solution

SI = PRT/100
=> 2018*3*14/100 = 847.56

Option 7)

Correct Option: 7 Best Solution (0)

15 Mar 2018 Age

A is six years older than B who is six times as old as C. The total of the ages of A, B and C is 123. How old is C?

OPtion

1) 17.5
2) 18
3) 18.5
4) 9
5) 19.5
6) 10
7) 54
8) 60
9) 27
10) None of these

Solution

As per question,
A+B+C =123
A-B=6
and B/C = 6


B+6+ (B+B/6) =123
=> 2B+B/6 = 117
=> 13B = 6*117
=> B = 54

So C = B/6 = 54/6 = 9

Correct Option: 4 Best Solution (0)