how many gallons of a 80% antifreeze solution must be mixed with 100 gallons of 30% antifreeze to get a mixture that is 70% antifreeze? Use the six-step method

Answer 1

.8x +.3(100) = .7(x+100)

.8x = .7x +70- 30

.1x = 40

x = 40/.1 = 400 gallons of 80% mixed with 100 gallons of 30% to get 4100 gallons of 70%

80-70 = 10

70-30 =40

40/10 =4 = 400/100