 Hello and welcome to the session. In this session we are going to discuss the following question and the question says that Find the rate of interest per annum so that a sum of money triple itself in 10 years. We know the formula a is equal to p into 1 plus n into i where a denotes the sum of the bill p is the present wealth n is the number of years and i is the interest of 1 dollar for 1 year. With this key idea let us proceed with the solution. We need to find the rate of interest per annum when the sum of money triple itself and the time given is 10 years. We know that here a is equal to thrice of p and the number of years that is n is given as 10 and we need to find the value of i. From the key idea we know that a is equal to p into 1 plus n into i so we have a is equal to p into 1 plus n into i and we know that a is equal to thrice of p that is 3p is equal to p into 1 plus n is equal to 10 into i which implies that 3 is equal to 1 plus 10 into i which can be written as r upon 100 that is 3 is equal to 1 plus we have 3 minus 1 that is 2 is equal to r upon 10 which implies that r is equal to 20. Therefore the required rate of interest is 20% per annum which is the required answer is complete and session hope you enjoyed this session.