M gallons of a p% salt solution must be mixed up with G gallons of a q% salt solution to produce an r% solution. Which of the following best describes how to find the value of r? (This question is driving me insane.)
(A) (p + g) / (M + G) = r / 100
(B) (0.01p + 0.01q) / (M + G) = r / 100
(C) 0.01p / M + 0.01q / G = r / 100
(D) (0.01M + 0.01G) / (M + G) = r / 100
(E) (0.01pM + 0.01qG) / (M+G) = r / 100
Break the parts down.
“M gallons of a p% solution”:
“G gallons of a q% solution”:
The r% solution will be M + G gallons, so:
The setup, then, is this:
That simplifies to :
This really isn’t a realistic SAT question, though. If you got this out of an SAT prep book, you’re being led astray.