You mix 1/3
quart of blue paint for every 1/2
quart of red paint to make 2 1/2
quarts of purple paint. how much blue paint and how much red paint do you use?

1 quart blue + 1 1/2 quart red

Step-by-step explanation:

Given:

Ratio of blue paint : red paint = 1/3 : 1/2

simplifying this ratio into whole numbers by multiplying both sides by 2 and 3, we get:

(1/3) x (3x2) : (1/2) x (3x2)

2 : 3

From this we can determine the fractions of red and blue paint used in any total purple mix

fraction of blue paint = 2/(2+3) = 2/5 of purple mix

fraction of red paint = 3/(2+3) = 3/5 of purple mix

we are given that we want to make 2 1/2  (= 5/2) quarts of purple paint

hence

amount of blue paint

= fraction of blue paint in purple mix x total amount of purple paint

= (2/5) x (5/2) = 1 quart

amount of red paint

= fraction of redpaint in purple mix x total amount of purple paint

= (3 /5) x (5/2) = 3/2 quart = 1 1/2 quart