A man has a solution that is 35% iodine and 65% water, and another that is 15% iodine.

Question

A man has a solution that is 35% iodine and 65% water, and another that is 15% iodine. How many gallons of the 15% solution should he combine with the first solution to get 2500 gallons of a 20% iodine solution?

(A) 1000

(B) 1875

(C) 2250

(D) 625

(E) None of these

I got (B) 1875. Would this be the correct answer?

Answer 1

Let x = number of gallons of 15% solution

Then, 2500 - x = number of gallons of 35% solution

0.15x + 0.35(2500 - x) = 0.20(2500)

0.15x + 875 - 0.35x = 500

-0.20x = -375

x = 1875 gal

Answer 2

x35%iodine

+y65%water

+z15%iodine

=2500g/20%

Since x and y have no value; I can't tell you anything about z.