Ifa sum of money doubles itself in 10 years, then the rate of simple interest is:

The sum of money doubles itself in 10 years.

Time (T) = 10 years.

Principal (P) is the initial sum, and Amount (A) is double the principal,

so A = 2P.

The formula for simple interest (SI) is:

​$$SI = \frac{P \times R \times T}{100}​$$​​

Where:

P = Principal

R = Rate of interest

T = Time in years

The relationship between the amount (A), principal (P), and simple interest (SI) is:

A = P + SI

Since the sum doubles in 10 years,

So, A = 2P.

SI = 2P - P = P

Now, using the formula for SI ,

​$$P = \frac{P \times R \times 10}{100}$$​​

100 = R × 10

R = $$\frac{100}{10}$$​ = $$10\%$$​​

Thus, The rate of simple interest is 10%.