Question

If a certain sum amounts to double the principal in 6 years, then the rate of simple interest is:

a) 12.5%
b) 16.67%
c) 25%
d) 50%

Answer 1

The rate of simple interest that doubles the principal in 6 years is found using the formula for simple interest and is calculated to be 16.67%, which corresponds to option b).

Step-by-step explanation:

To determine the rate of simple interest that leads to a sum doubling over 6 years, we can use the formula of simple interest:

I = P × r × t

Where I is the interest earned, P is the principal amount, r is the rate of interest per year, and t is the time in years.

According to the question, the final amount is double the principal, which means the interest earned equals the principal. This gives us:

P = P × r × 6

Canceling out the principal from both sides, we get:

1 = r × 6

To find the rate r, we divide both sides by 6:

r = 1/6

Converting this to a percentage:

r = (1/6) × 100% = 16.67%

Therefore, the correct answer is b) 16.67%.