Money invested by six persons A–F at simple interest, with rate, time and a rupee value. Dashes are missing and to be calculated.

Person	Rate of Interest	Time	Value (Rs)
A	6%	—	18000
B	6%	—	30000
C	—	5 years	29000
D	—	3 years	45000
E	8%	—	20000
F	—	2 years	60000

If the rate of interest received by A and C is in the ratio 2:3, then the money invested by C will get doubled in how many years?

A12 and half

B15 and one-seventh

C13 and one-third

D11 and one-ninth ✓ Correct

Correct answer: (D) 11 and one-ninth

Explanation

The money invested by C will double in 11 and one-ninth years.

A's rate is 6 percent, and the ratio of A's rate to C's rate is 2 to 3.

So C's rate is 6 times 3 over 2, which is 9 percent.

For the sum to double on simple interest, the interest must equal the principal.

This needs the rate times the time to equal 100.

So the time is 100 over 9, which is 11 and one-ninth years.

Want more like this? Create a free account to practise a full test, track your progress, and get spaced-repetition review.