Math Question Needed to be Answered

Question

What amount of a 60% acid solution must be mixed with a 35% solution to produce 500 mL of a 40% solution?

Answer 1

.6x + .35(500-x) = 500(.4)

.6x - .35x = (.4 -.35)(500)

.25x = .05(500) = 25

x= 25/.25 =100 mL of 60% mixed with 400 mL of 35% to get 500 mL of 40%

35 is within 5 of 40

60 is within 20 of 40

20/5 = 4

you need 4 times as much 35% as 60%

400/100 = 4