What do you call a relation in which each element of the domain is paired with exactly one element of the range

Tori examined the pattern of exponents in the table. based on the pattern, which statements are true? check all that apply.

What is the smallest integer n such that n\sqrt{2} is greater than 20

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?