2,800 रुपये पर 10% प्रति वर्ष की दर से 3 वर्ष में अर्जित साधारण ब्याज x रुपये है, और 6,200 रुपये पर 14% प्रति वर्ष की दर से y वर्ष में अर्जित साधारण ब्याज 1,736 रुपये है। xy का मान क्या है?

A sum becomes 25 times of itself when invested for 48 years at r% simple interest per annum. Find the compound interest earned if Rs. 51,200 is invested at r% per annum when interest is compounded half-yearly, for 1.5 years.

Simple interest on a certain sum at 4% per annum for 2 years is ₹80. What is the compound interest on the same sum for the same period at the same rate?