i dont know if i am doing this wrong but i got non-fiction, fiction, children, school but it is not an option can someone double check

An unknown number of kids and buses are getting assigned. when assigning 4 kids to each bus, there are 2 kids that aren't placed in a bus. when assigning 8 kids to each bus, there are 2 empty buses. how many total kids are there?

Factor the expression using gcf 9b+45

What is the geometric mean of 3 and 7? a) square root of 21 b) 2 square root of 6 c) 2 square root of 7 d) 21