solving the solutions

[sanju09]

How many ounces of a solution that is 30 percent salt must be added to a 50-ounce solution that is 10 percent salt so that the resulting solution is 20 percent salt?

(A) 20
(B) 30
(C) 40
(D) 50
(E) 60

[scoobydooby]

let x ounces of solution be added

amount of the salt in the resulting solution: 5+0.30x
amount of the resulting solution: 50+x

given (5+0.30x)/(50+x)=1/5
=>3/2*x-x=50-25
=> x=50

hence, D