Help ME this is the last one

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?

Which math sentence can be used to determine if the triangle is a right triangle?

Diana is painting statues she has 7/8 of a liter of paint each statue requires 1/20 of a liter of paint how many statues can she paint?