bob was interested in this investment. after calling to make sure that the 100$ fee would be deducted after his money was doubled, he decided to join. However , after his service charge was deducted at the the end of four months his balance was exactly 0! How much money did he start out with?
He must have started with $50 ....when it DOUBLED to $100 and they deducted the fee ($100) , it would be ZERO.