## Aptitude Question

Aptitude Solved Problems

Questions :

1. Certain sum becomes 2 times itself at compound interest in 4 years. In how many years it becomes 8 times?

2. A man can row 6 Km / hr in still water. If the velocity of the current is 3 Km / hr and it takes him 4 hours to row to a place and come back. How far is the place?

3. Two employees M and N are paid a total of Rs. 550 per week by their employer. If M is paid 120 percent of the sum paid to N, how much is N paid per week?

Answers :

1. 12 years

2. 9 km

3. Rs. 250

1. Explanation:

Amount = Principal * ( 1 + ( Rate / 100 ))n

P * ( 1 + ( R/100 ) )4 = 2P

(1 + ( R / 100 ) )4 = 2 ………. ( 1 )

Let P(1 + ( R / 100 ) )n = 8P

(1 + ( R / 100 ) )n = 8

(1 + ( R / 100 ) )n = 23 …………… ( 2 )

Equating ( 1 ) and ( 2 )

23 = [ (1 + ( R / 100 ) )4]3

23 = (1 + ( R / 100 ) )12

(1 + ( R / 100 ) )n = (1 + ( R / 100 ) )12

n = 12 years

∴ Number of years = 12 years

2. Explanation:

Man′s rate down stream = 6 + 3

= 9 km / hr

Man′s rate upstream = 6 – 3

= 3 km / hr

Let the required distance be x km

Distance / Speed = time

( x / 9 ) + ( x / 3 ) = 4

( x + 3x ) / 9 = 4

x + 3x = 4 * 9

4x = 36

x = 36 / 4

∴ x = 9 km

∴ Required distance = 9 km

3. Explanation:

Let the amount paid to M per week = a

The amount paid to N per week = b

Then a + b = Rs. 550

But a = 120% of b

= 120b / 100

= 12b / 10

( 12b / 10 ) + b = 550

b * [ ( 12 / 10 ) + 1 ] = 550

b * ( ( 12 + 10 ) / 10 ) = 550

b * ( 22 / 10 ) = 550

22b = 550 * 10

= 5500

b = 5500 / 22

= 500 / 2

= Rs. 250

∴ The amount paid to N per week = Rs. 250