Find the LCM (in this case, it's 12)
8/12 red
3/12 yellow
Make 3/12 a full quart by multiplying by 4
3/12 x 4/1 = 1
Since you multiplied 3/12 with 4, do the same with red
8/12 x 4/1
SIMPLIFY TO MAKE EASIER
8/3 x 1
You use 2 2/3 quarts of red paint for every quart of yellow paint