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

20y5 times 2 is 1010 times -2 is -20, plus y