Question 581415
"A chemist has a 90% solution of sulfuric acid and a 70% solution of the same acid.
 How many gallons of each must be mixed in order to make 200 gallons of 75% solution?"
:
We can do it this way
:
Let x = amt of 90% solution
the resulting amt is to be 200 gal, therefore
(200-x) = amt of 70% solution
:
.90x + .70(200-x) = .75(200)
solve for x, to get the 90% amt, then subtract that from 200 to get the 70%