You mix 2/5 cup of red paint for every 1/4 cup of blue paint to make 1 5/8 gallons of purple paint. How much red paint and blue paint do you use

Answer=16 cups of red and 10 cups of blue

2/5=8/20=32/80

1/4=5/20=20/80

1 5/8gallons=26cups

32/80+20/80=52/80

26=x (52/80)

divide both sides by (52/80)

40=x

In short, you multiply the mixture by 40, so ...

40*2/5=16cups of red

40*1/4=10cups of blue