Question

How much water should be added to 90ml of 45 percent acid solution to dilute it to 25 percent acid solution

Answer 1

72 ml

Explanation:

Let

x = amount of water that should be added

45% acid solution = 45/100 = 0.45

25% acid solution = 25/100 = 0.25

The equation is

90(0.45) = 0.25(x + 90)

40.5 = 0.25x + 22.5

40.5 - 22.5 = 0.25x

18 = 0.25x

Divide both sides by 0.25

x = 18/0.25

= 72

x = 72 ml