The question is:

The answer is 9. However here is how i approached it.A solution of 27 gallons of acid contains 9 gallons of pure acid.How much water in gallons should be added to produce a 25% solution of this acid ?

Equation is :

Quantity %age Cal water x 100% x acid solution 27 9/27 or (33.33%) 0.33 x 27 = 9 Required Solution x+27 25% Equation

x+9 = 0.25(x+27)

x+9 = 0.25x + 6.75

Could anyone tell me what am i doing wrong i am getting a negative value ??