Need help 8th grade math

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?

41/2 - 1 1/3 what is the answer as a fraction?

Fredrick designed an experiment in which he spun a spinner 20 times and recorded the results of each spin