The school will have to pay $18 for 15 dozen buttons how much will the school have to pay for 50 dozen buttons

It will cost the school $60

Step-by-step explanation:

In order to find this, set up a proportion.

$18/15 dozen = $x/50 dozen

Now cross multiply to solve

50 * 18 = 15 * x

900 = 15x

60 = x