One inch of board is left if you subtract the two 3 inches pieces from the board the further subtract the 24 inches from the three 8 inches pieces you get 31-30
When you deposit money in a bank, the bank usually pays you for the use of your money. When you take out a loan from a bank, you have to pay the bank for the use of their money. In both cases, the money paid is called the interest. It is usually expressed as a percent. Here we shall look at a formula for simple interest.