What is the equation for the (graph) line?

Really need on these. i have no idea what to do

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

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?