Question

125 gallons of a mixture contains 20% water.what amount of additional water should be added such that water content be raised to 25%

Answer 1

The initial amount of water in the gallons is :

20/100 × 125 = 25gallons

Let the amount of water to be added be x.

The new amount of water is :

x + 25

The new amount of the mixture = x + 125

We express this as a percentage of the total mixture :

(x + 25) / (x + 125) × 100 = 25

100x + 2500 = 25x + 3125

100x - 25x = 3125 - 2500

75x = 625

x = 8,1/3 gallons of water

Answer 2

(125 gallons * 0.2) + x gallons = (125 gallons + x gallons) * 0.25

25 gallons + x gallons = 31.25 gallons + 0.25x gallons

(x-0.25x) gallons = (31.25–25) gallons

0.75x gallons = 6.25 gallons

x gallons = 8.33 gallon