M gallons of a p% salt solution must be mixed up with G gallons of a q% salt solution to produce an r% solution.

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

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