Compound interest

Reena borrowed from Kamal certain sum for two years at simple interest. Reena lent this sum to Hamid at the same rate for two years compound interest. At the end of two years she received Rs 110 as compound interest but paid Rs 100 as simple interest. Find the sum and rate of interest.

Compute the compounded interest on Rs 12000 for 2 years at 20% per annum when compounded half-yearly.

A certain sum amounts to Rs 5832 in 2 years at 8% compounded interest. Find the sum.