Question

Kelsey is putting on sunscreen. She uses 3 ml to cover 45cm to the power of 2 of her skin. She want to know how many milliliters of sunscreen (g) she needs to cover 240cm to the power of 2 of her skin. She assumes the the relationship between milliliters of sunscreen and the area is proportional.
How many milliliters of sunscreen does Kelsey need to cover 240cm to the power of 2 of her skin?

Answer 1

Answer: She would require 16 ml cover 240cm^2 of her skin

Step-by-step explanation:

Let m represent the milliliters of sunscreen required to cover her skin.

Let a represent the area of her skin that was covered. She assumes the the relationship between milliliters of sunscreen and the area is proportional. Introducing the constant of variation, k, the expression becomes

m = ka

She uses 3 ml to cover 45cm^2 of her skin. Therefore,

3 = k × 45

k = 3/45 = 1/15

The expression becomes

m = a/15

The milliliters of sunscreen that Kelsey needs to cover 240cm to the power of 2 of her skin would be

m = 240/15

m = 16 ml