The simple interest on a sum of money is 1/9 of the principal and the number of years is equal to the rate per cent per annum. The rate percent per annum is :

The simple interest on a sum of 

money is 1/9 of the principal and 

the number of years is equal to the

 rate per cent per annum. The rate

 percent per annum is : 

(a) 3
(b) 1/3
(c) 10/3
(d) 3/10

Correct answer: c

Solution :