M4maths Previous Puzzles

19 Jun 2019 Speed

On a journey, across Bangalore, a cab averages 12 kmph for 60% of the distance, 15 kmph for 20% of it and 30kmph for the remainder. The average speed for the whole journey is :

OPtion

1) 13.50
2) 14.70
3) 14.80
4) 15.50
5) 14.45
6) 14.29
7) 15.50
8) 15.70
9) 15.29
10) None of these

Solution

Lets assume that total distance is 100 KMs

So for 60 KMS time take = 60/12 = 5 Hours
For 20 KMS time take = 20/15 = 4/3 hours
For remainder 20 KMS time take = 20/30 = 2/3 hours

Total Time taken = 5 + 4/3 + 2/3 = 7 hours

Average speed = 100/7 = 14.29 KMPH

Correct Option: 6 Best Solution (4)

18 Jun 2019 Pipe

A tap can fill a tank in 30 minutes another tap can empty it in 1.5 hours. if both the taps are opened at 11.40 am. then at what time will the tank be filled?

OPtion

1) 1:00 PM
2) 12:25 PM
3) 1:25 PM
4) 12:45 PM
5) 1:30 PM
6) 12:50 PM
7) 1:15 PM
8) 12:35 PM
9) 1:20 PM
10) None of these

Solution

1 min. filling =1/30
1 min. empty=1/(1.5*60)
In 1 min. tank will be filled (1/30)-[1/(1.5*60)] = 1/30 - 1/90 = (3-1)/90 = 1/45
So tank will completely filled in 45 min. from the start
So 11:40 + 45 min = 12:25 PM

Correct Option: 2 Best Solution (0)

17 Jun 2019 Profit & Loss

Robert purchased a machine for Rs. 80,000. After spending Rs.5000 on repair and Rs.1000 on transport he sold it with 125% profit. What price did he sell the machine?

OPtion

1) 107500
2) 108500
3) 109500
4) 106500
5) 193500
6) 104500
7) 194500
8) 198500
9) 195500
10) None of these

Solution

CP of Machine for John include all costs = 80000 + 5000 + 1000 = 86000
SP = 225 * 86000/100 = 193500

Correct Option: 5 Best Solution (10)

14 Jun 2019 Age

The present age of a brother is 2 years more than four times the age of his sister. Two years hence, brother’s age will be 4 years more than twice the age of the sister. Find the present age of the brother.

OPtion

1) 8
2) 12
3) 10
4) 15
5) 16
6) 14
7) 11
8) 18
9) 13
10) None of these

Solution

Let the sister’s present age be ‘n’ years.
=> brother’s present age = (4n + 2) years
So, according to the question
(4n + 2 + 2) = 2 (n + 2) + 4
=> 4n + 4 = 2n + 8
=> n = 2
Hence, brother’s present age = (4n + 2) = 10 years

Correct Option: 3 Best Solution (5)

13 Jun 2019 Series

What is the next term of following series:
377, 610, 987, 1597, ?

OPtion

1) 2591
2) 2584
3) 2577
4) 2533
5) 2595
6) 2593
7) 2388
8) 2567
9) 2587
10) None of these

Solution

Series is formed by Fibonacci numbers starting at 377 and 610 so next number is 987 + 1597 = 2584
Option 2)

Correct Option: 2 Best Solution (3)

12 Jun 2019 Time and Work

It takes Mr. Rahul y hours to complete an assignment. After 3 hours, he was called away. What fractional part of the assignment was left incomplete?

OPtion

1) y/3
2) 3/y
3) (1/y - 3)
4) (3/y -1)
5) (1-3y)y
6) (y-3)/y
7) (y-3/y)
8) 1/7y
9) y/7
10) None of these

Solution

for 1 hour he will do 1/y work...
for 2 hour he will do 2/y work...
So for 3 hours he will do 3/y work...
remaining work= 1-(3/y)
therefore answer is (y-3)/y.

Correct Option: 6 Best Solution (3)

11 Jun 2019 Odd man out

Find the odd man out from the following series:
2, 3, 5, 7, 11, 13, 17, 19, 21, 23,

OPtion

1) 2
2) 3
3) 5
4) 7
5) 11
6) 13
7) 17
8) 19
9) 21
10) 23

Solution

Except 21 rest all prime numbers

Correct Option: 9 Best Solution (7)

10 Jun 2019 Average

The price of a product was reduced by 35% last year. During this year by what percentage should it be increased to bring it back to the original price of last year?

OPtion

1) 52.67
2) 42.17
3) 53.85
4) 51.06
5) 52.58
6) 12.05
7) 53.36
8) 53.76
9) 53.80
10) None of these

Solution

If initial price is Rs 100 and reduced price is Rs 65.

Then to make it 100 again, price should increase by 100*35/65= 53.85

Correct Option: 3 Best Solution (5)

07 Jun 2019 Distance Traveled

A tempo, while travelling at 70 kmph, uses 40% more petrol than it uses while travelling at 50 kmph for travelling a certain distance. Using one litre of petrol, it can travel 19.6 km at 50 kmph. How far can the tempo travel (in KMs) on 10 litres of petrol at a speed of 70 kmph?

OPtion

1) 140
2) 240
3) 248
4) 560
5) 260
6) 270
7) 280
8) 300
9) 180
10) None of these

Solution

At 50 kmph , one km distance uses 1/19.6 litre petrol.
At 70kmph, one km distance uses 1.4/19.6 litre petrol
Distance traveled with 10 ltrs @ 70kmph = 10*19.6/1.4= 140 kms.

Correct Option: 1 Best Solution (6)

06 Jun 2019 Factors

How many factors of 1230356435 are odd number?

OPtion

1) 12
2) 80
3) 16
4) 60
5) 30
6) 14
7) 20
8) 15
9) 24
10) None of these

Solution

1230356435 = 5^1 * 7^5 *11^4

Any factor of this number should be of the form 5^a * 7^b * 11^c.

For the factor to be a odd number a,b,c can take any value as product of 3 odd numbers would always be odd

a can take values 0, 1
b can take values 0, 1, 2, 3, 4, 5
and c can take values 0, 1, 2, 3, 4

Total number of odd factor = 2 * 6 * 5 = 60

Correct Option: 4 Best Solution (2)