Find the ratio of the simple interest and the compound interest on ₹100 at 10% per annum for 2 years, if, when compounded, interest is compounded annually.

20 : 21

Simple Interest = \(\frac{Principal ×Rate × Time }{100}\)

= \(\frac{100 ×10 × 2 }{100}\)

= 20

Compound Interest = Principal × ( 1 + \(\frac{rate}{100}\) )t - Principal

= 100 × ( 1 + \(\frac{10}{100}\) )² - 100

= 100 × \(\frac{11}{10}\) × \(\frac{11}{10}\) - 100

= 121 - 100

= 21

So , Ratio of simple interest to compound interest = 20  :  21