+81 1)How many perfect squares are there between 20 and 150?
2)How many ways can we put 3 math books and 5 English books on a shelf if all the math books must stay together and all the English books must also stay together? (The math books are all different and so are the English books.)
T-T i cant do it :(
1. There are seven perfect squares between 20 and 150.
2. There are 3!*5! = 720 ways to arrange the books.
Hope this helps!
