S3 Maths questions

Please to answer the following question

1. John deposited $50 000 in a bank at 3% p.a. for 4 years. At the same
time, Mary borrowed $40 000 from the same bank for 2.5 years. What interest
rate should the bank charge Mary in order to cover the simple interest
earned by Mary's deposit?


2. Mrs Tse, borrowed some money from a bank at a simple interest rate of
8% p.a.. If she has to pay as much interest as the principal, find the
period she borrowed the money.