3. Exercise 4.3.3 Michael invests Birr 2000 in the bank that pays simple interest rate of 5% per year for 6 years. Then how much interest will he get in 6 years? Birr 24000 invested at 11% simple interest per annum, then what is the amount after 8 years? How long will it take for Birr 15000 to double itself, if it is invested at simple interest rate of 10% per year. 4. If Birr 20,000 grows to Birr 28000 after 20 years. Then what is the simple interest rate? 5. In how many years will Birr 12,000 yield an interest of Birr 1200 at 5% simple interest? 6. An investment earned Birr 2100 interest after 6 years. If the simple interest rate is 7% per year. What was t
he principal?​