1)A sum of money at simple interest amounts to Rs. 614 in 3 years and to Rs. 654 in 4 years. The sum is:

A. Rs. 494

B. Rs. 500

C. Rs. 510

D. Rs. 520

Answer:A. Rs. 494

Explanation:
Simple interest for 1 year = Rs. (654 - 814) = Rs. 40.
Simple interest for 3 years = Rs.(40 x 3) = Rs. 120.
Principal = Rs. (614 - 120) = Rs. 494.

2) How much time will it take for an amount of Rs. 500 to yield Rs. 80 as interest at 5% per annum of simple interest?

A. 3.5 years

B. 3.2 years

C. 4.5 years

D. 5.2 years

Answer:B. 3.2 years

Explanation:
Time =
(100 x 80 /500 x 5) years
= 3.2 years.

3) Divya took a loan of Rs. 1600 with simple interest for as many years as the rate of interest. If she paid Rs. 400 as interest at the end of the loan period, what was the rate of interest?

A. 5

B. 6

C. 7

D. None of these

Answer:A. 5

Explanation:
Let rate = R% and time = R years.
Then, (1600 x R x R /100) = 400
16R2 = 400
R2 = 400/16=25
R = 5.

4) A sum of Rs. 14,000 amounts to Rs. 16,000 in 3 years at the rate of simple interest. What is the rate of interest?