M4maths Previous Puzzles

18 Jul 2018 Fraction

Which of the following fractions is greater than 4/5 and less than 5/6 ?

OPtion

1) 2/3
2) 7/8
3) 3/5
4) 7/9
5) 11/14
6) 9/11
7) 6/7
8) 7/9
9) 11/13
10) None of these

Solution

By resolving fractions to decimal, we could see
4/5 = 0.80 and
5/6 = 0.83

From given options, 9/11 = 0.82 which is greater than 4/5 and less than 5/6

Correct Option: 6 Best Solution (20)

17 Jul 2018 Simple Interest

A person borrows Rs. 75000 for 9 years at 5.5% p.a. simple interest. He immediately lends it to another person at 9.25 p.a for 9 years. Find his gain in the transaction per year.

OPtion

1) 25312.5
2) 5625.00
3) 12812.50
4) 9043.75
5) 5675.00
6) 2012.50
7) 9643.75
8) 5675.00
9) 2612.50
10)None of these

Solution

SI on borrowing = 75000*9*5.5/100 = 28875

SI on Lending = 75000*9*9.25/100 = 48562.5


Gain per year = (48562.5 - 28875)/9 = 2812.5

Option 10)

Correct Option: 10 Best Solution (4)

16 Jul 2018 Series

Find the next term of following series
1, 6, 13, 22, ..

OPtion

1) 34
2) 33
3) 35
4) 37
5) 31
6) 36
7) 47
8) 45
9) 41
10) None of these

Solution

In this sequence, the next term is evaluated by the expression:
n^2 - 3 where first term is 2

So 5th term is 6^2 -3 = 33

Correct Option: 2 Best Solution (7)

13 Jul 2018 Trains

Two trains each 333 meter long, are running in opposite directions on parallel tracks. If their speeds are 45 km/hr and 66 km/hr respectively, the time taken by the faster train to pass the driver of the slower one is?

OPtion

1) 7.5 seconds
2) 9.1 seconds
3) 8.9 seconds
4) 9.0 seconds
5) 10 seconds
6) 9.5 seconds
7) 10.8 seconds
8) 8.5 seconds
9) 10.6 seconds
10) None of these

Solution

Relative speed= 66+45 = 111 km/hr = 111 * 5/18 = 185/6 m/sec

We are calculating the time taken by the faster train to pass the driver of the slower one.
Hence, distance = length of the faster train = 333 meter

Time = 333/185/6 = 10.8 seconds

Option 7)

Correct Option: 7 Best Solution (8)

12 Jul 2018 Work & Time

If 11 men and 16 women can do a piece of work in 6 days and 7 men and 9 women can do it in 10 days,

how many days will 15 women and 5 men take to do it?

OPtion

1) 7.75
2) 8.00
3) 8.25
4) 8.50
5) 8.70
6) 9.00
7) 9.25
8) 8.66
9) 9.75
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 = 6(11x + 16y) = 10(7x + 9y)

Solving we get, 66x - 70x = 90y - 96y
=> 4x = 6y
=> 2x = 3y


Now, 11 x + 16 y can do work in 6 days.
So, 33y/2 + 16 y can do work in 6 days.
So, 65y/2 can do work in 6 days.

Now, 5x + 15y = 15y/2 + 15y = 45y/2

Hence, if 65y/2 can do work in 6 days, 45y/2 can do work in ((65y/2)*6)/45y/2 = 8.66 days.

Option 8)

Correct Option: 8 Best Solution (1)

11 Jul 2018 Perfect Square

How many factors of 16295655600 are perfect squares?

OPtion

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

Solution

16295655600 = 53^1 * 83^1 * 7^3 * 5^2 * 2^4 * 3^3

Any factor of this number should be of the form 53^a * 83^b * 7^c * 5^d * 2^e * 3^f.

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

a can take values 0,
b can take values 0,
c can take values 0, 2
d can take values 0, 2
e can take values 0, 2, 4
and f can take values 0, 2


Total number of perfect squares = 1*1*2*2*3*2 = 24

Option 6)

Correct Option: 6 Best Solution (3)

10 Jul 2018 Profit and Loss

1080 bananas are bought for Rs. 2520 and sold at the rate of Rs. 35 per dozen. The percentage of profit or loss is:

OPtion

1) 2.5 % Profit
2) 12.5 % Profit
3) 25.00 % Loss
4) 35.555 % Profit
5) 36.6666 % Loss
6) 37.7777 % Profit
7) 25.00 % Profit
8) 32.222 % Loss
9) 34.5 % Profit
10) None of these

Solution

Cost of 1 banana= 2520/1080 = 2.33333
Selling price of 1 banana = 35/12 = Rs. 2.91667

As SP > CP so its profit
So Profit % = (2.91667 - 2.33333 )*100/2.33333 = 25 %

Option 7)

Correct Option: 7 Best Solution (8)

09 Jul 2018 Series

Find the eighth term of the following series:
101, 102, 104, 107, 111, 116, ...

OPtion

1) 129
2) 124
3) 122
4) 120
5) 126
6) 127
7) 121
8) 125
9) 128
10) None of these

Solution

In this addition series, 1 is added to the first number; 2 is added to the second number; 3 is added to the third number; 4 is added to the fourth number; and so on.

So 116+6 = 122 and
122+7 = 129

Correct Option: 1 Best Solution (1)

07 Jul 2018 Age

Mr. Thanos is 24 years older than his son. In two years, his age will be twice the age of his son. What is the present age of his son?

OPtion

1) 16
2) 19
3) 18
4) 20
5) 22
6) 17
7) 21
8) 23
9) 24
10) None of these

Solution

Let Son's age be x
So Thanos's Age is = x+24

2 Years Later
Son's age = x+2
Thanos's age = x+26

As per question, 2*(x+2) = x+26
=> 2x+4 = x+26
=> x = 22

Correct Option: 5 Best Solution (7)

06 Jul 2018 Percentage

NOTE: This week's Today's Puzzle contest is extended till Saturday. We could not post a Puzzle on Thursday due to Technical issues.


If Rs.78300 is to be divided among Amar, Akbar and Anthony so that Amar receives 30% more than Akbar and Akbar receives 30% less than Anthony, then Amar's shares is

OPtion

1) Rs.27030
2) Rs.23700
3) Rs.27380
4) Rs.21000
5) Rs.30000
6) Rs.23000
7) Rs.27700
8) Rs.28800
9) Rs.25000
10) None of these

Solution

Suppose Anthony's gets Rs.100 then Akbar gets Rs.70
Amar gets = 30% more than Akbar = 70*130/100 = 91

Aamr:Akbar:Anthony = 91:70:100

Therefore Aamr's share = (91/261)*78300 = Rs. 27300
Option 10)

Correct Option: 10 Best Solution (0)