कोई धनराशि साधारण ब्याज के तहत 2.5 वर्षों में दोगुनी हो जाती है। वह कितने वर्षों में स्वयं की 42 गुनी हो जाएगी?

A sum becomes 2215 of itself in 6 years at simple interest. Find the rate of interest per annum.

In how many years will a sum of ₹5,500 amount to ₹6,600 at a simple interest rate of 5% per annum?

A sum of money amounts to ₹16000 in 6 years at simple interest of 25 percent per annum. What will be the total interest for 6 years?