# Simple Interest

1. At what rate percent of simple interest per annum will a sum of money double in 8 years.

A. 12.5%

B. 13.5%

C. 11.5%

D. 14.5%

Explanation:

Let principal = P, Then, SI = P after 8 years

We know that SI = PTR/100 = P

Rate = [(100 x P)/ (P x 8)]% = 12.5% per annum

2. How much time will take for an amount of Rs. 450 to yield Rs. 81 as interest at 4.5% per annum of simple interest  ?

A. 4 years

B. 2.5 years

C. 3.5 years

D. 2 years

Explanation:

SI = PTR/100
Time = (100 x 81) / (450 x 4.5) = 4 years

3. A sum was put at simple interest at a certain rate for 3 years. Had it been put at 2% higher rate, it would have fetched Rs 360 more. Find the sum.

A. Rs.4000

B. Rs.9000

C. Rs.5000

D. Rs.6000

Explanation:

Let sum = P and original rate of interest = R
Then, [(P * (R+2) * 3)/100] - [ (P * R * 3)/100] = 360

=> 3P*(R+2) - 3PR = 36000
=> 3PR + 6P - 3PR = 36000
=> 6P = 36000
=> P = 6000

4. A certain sum earns simple interest of Rs. 1750 in 7 years. Had the interest been 2% more, how much more interest would it have earned?

A. Rs.35

B. Rs.245

C. Rs.350

D. cannot be determined

Explanation:

We need to know the S.I, principal and time to find the rate. Since the principal is not given, so data is inadequate.

5. The difference between the simple interest received from two different sources on Rs. 3000 for 3 years is Rs. 27. The difference between their rates of interest is:

A. 0.1%

B. 0.2%

C. 0.3%

D. 0.4%