PLEEEASE HELP! AND IF U CAN EXPLAIN HOW YOU GOT THE ANSWER, THAT WOULD HELP SO MUCH :)

You are constructing a histogram for scores that range from 70 to 100 in whole points. frequencies range from 3 to 10; that is, every whole-point score between 60 and 100 occurs at least 3 times, and at least one score occurs 10 times. which of these would probably be the best range and size for the score intervals along the x-axis?

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?

You deposit $5000 each year into an account earning 3% interest compounded annually. how much will you have in the account in 30 years?