Question

A certain shade of light blue paint is made by mixing `1\frac{1}{2}` quarts of blue paint with 5 quarts of white paint. How much white paint would you need to mix with 4 quarts of blue paint?

Answer 1

Let $x=$ the amount of white paint mixing with 4 quarts of blue paint.

We can make a proportion

$$\dfrac{1{1 \over 2}}{5}=\dfrac{4}{x}$$

Solve for $x$

$$\dfrac{3}{2}x=4(5)$$

$$x=20(\dfrac{2}{3})$$

$$x=\dfrac{40}{3}$$

$$x=13{1 \over 3}$$

We need to mix $13{\dfrac{1}{3}}$ quarts of white paint with 4 quarts of blue paint.