The simplest way to think about this is that the half life has elapsed 3 times, so you need to take the initial mass and divide it by 2 3 times, so 784/2/2/2 or 784/8 which is 98
The person must invest the money in the bank for 18 years to reach $19600, if a person invests 9000 dollars in a bank and the bank pays 4.25% interest compounded daily.
