Find the value of x. I need some help

Yoku is putting on sunscreen. he uses 2\text{ ml}2 ml to cover 50\text{ cm}^250 cm 2 of his skin. he wants to know how many milliliters of sunscreen (c)(c) he needs to cover 325\text{ cm}^2325 cm 2 of his skin. how many milliliters of sunscreen does yoku need to cover 325 \text{ cm}^2325 cm 2 of his skin?

Ateacher noticed 5/8 of the students were wearing either blue shorts or white shorts. write two different ways this could be done.

Given the equation f(x)=a(b)x where the initial value is 40 and the growth rate is 20% what is f(4)