In how much time will a sum of money double itself at a rate of simple interest of 5% per annum?

Correct option is C

Given:

Amount becomes double

Rate of interest = 5%

Formula Used:

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

Amount = Principle + Interest

Solution:

Amount =$$2 \times Principle$$​

2P = P+SI

SI = P

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

​$$P = \frac{P\times 5\times T}{100}$$​​

​$$T = \frac{P\times 100}{P \times 5 }$$​​

T = 20 years