GeminiHeat wrote:
A convenience store currently stocks 48 bottles of mineral water. The bottles have two sizes of either 20 or 40 ounces each. The average volume per bottle the store currently has in stock is 35 ounces. How many 40 ounce bottles must be sold for the average volume per bottle to be reduced to 25 ounces if no 20 ounce bottles are sold?
(A) 10
(B) 20
(C) 30
(D) 32
(E) 34
Let the number of 20 ounce bottle be \(A\) and the number of 40 ounce bottles be \(B\)
\(A + B = 48\)
\(20A + 40B = 35(48) = 1680\)
Now, let \(x\) bottles of 40 ounce be sold to make average volume \(25\)
i.e. \(20A + 40(B - x) = 25(48 - x)\)
Equate \(20A\);
\(1680 - 40B = 25(48 - x) - 40(B - x)\)
\(1680 - 40B = 1200 - 25x - 40B + 40x\)
\(1680 - 1200 = 15x\)
\(x = 32\)
Hence, option D