In what time will the simple interest be 2/5 of the principal at 8 percent per annum? 

A sum of money becomes triple itself in 16 years. In how many years will it become 5 times at the same rate?

What sum will give Rs. 488 as the difference between simple interest and compound interest at 10% in $$ 1{1\over2}$$ years compounded half yearly ?

How much interest will be received in 2.5 years at the rate of 4 percent simple interest of Rs. 3,680?

Some amount out of Rs.7000 was lent at 6% per annum and the remaining at 4% per annum. If the total simple interest from both the fractions in 5 year was Rs.1600, find the sum lent at 6% per annum.

The annual payment of Rs.1000 in  5 years at 4% per annum simple interest will discharge a debt of

Mr. Dutta desired to deposit his retirement benefit of ₹3 lacs partly to a post office and partly to a bank at 10 % and 6 %  simple interests respectively. If his monthly interest income was ₹ 2000, then the difference of his deposits in the post office and in the bank was -