List of top Quantitative Aptitude Questions on Interest (SI & CI) asked in ATMA

A sum doubles itself in 8 years at simple interest. The annual rate of interest is:
The compound interest on Rs. 8,000 at 10% per annum for 2 years (compounded annually) is:
Find the simple interest on Rs. 6,000 at 8% per annum for 3 years.