Question

At what rate of simple interest will a sum of money double itself in 10 years?
Please tell the answer

Answer 1

Answer:

The answer is 9%.

Below is the rough but accurate way to calculate the simple interest from Investopedia.

The 'Rule of 72' is a simplified way to determine how long an investment will take to double, given a fixed annual rate of interest. By dividing 72 by the annual rate of return, investors can get a rough estimate of how many years it will take for the initial investment to duplicate itself.

For example, the rule of 72 states that $1 invested at 10% would take 7.2 years ((72/10) = 7.2) to turn into $2. In reality, a 10% investment will take 7.3 years to double ((1.10^7.3 = 2).

When dealing with low rates of return, the Rule of 72 is fairly accurate.

Hope it is helpful...

Answer 2

Answer:

5% p.a.

Step-by-step explanation:

SI = x            T = 10 Yrs

P = 2x            r be rate of interest

SI = PRT/100

x = 2x × R × 10/ 100

R = 100 × x / 2x × 10

R = 5 % p.a.