चक्रवृद्धि ब्याज के तहत, कोई धनराशि 7 वर्षों में अपने मूल मूलधन की दोगुनी हो जाती है। कितने वर्षों में यह अपने मूल मूलधन का 128 गुना हो जाएगी?

A person invested Rs. 2,000 in a bank at a rate of 5% per annum for 2 years. What is the compound interest he will get?

What is the compound interest (in ₹) on a sum of ₹18,000 at 20% per annum for 234 years, compounded annually?