SOLUTION: 140 litre of an acid contains 90% of acid and the rest water. How much water must be added to make the water 12.5% of resulting mixture?

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: 140 litre of an acid contains 90% of acid and the rest water. How much water must be added to make the water 12.5% of resulting mixture?      Log On


   

Question 704349: 140 litre of an acid contains 90% of acid and the rest water. How much water must be added to make the water 12.5% of resulting mixture?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
140 litre of an acid contains 90% of acid and the rest water.
How much water must be added to make the water 12.5% of resulting mixture?
:
let x = amt of water required
:
When the water amt is increased to 12.5%, the acid amt: 100 - 12.5 = 87.5%
:
.90(140) = .875(w+140)
126 = .875w + 122.5
126 - 122.5 = .875w
3.5 = .875w
w = 3.5/.875
w = 4 liters of water added