How many ways can 3 of 5 objects be arranged in a row?

Agreeting card company can produce a box of cards for $7.50. if the initial investment by the company was $50,000, how many boxes of cards must be produced before the average cost per box falls to $10.50?

Factor the monomial completely 42a3b3

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much