Bunuel wrote:
In a group of people solicited by a charity, 30 percent contributed $40 each, 45 percent contributed $20 each, and the rest contributed $12 each. What percentage of the total contributed came from people who gave $40?
(A) 25%
(B) 30%
(C) 40%
(D) 45%
(E) 50%
(A) 25%
(B) 30%
(C) 40%
(D) 45%
(E) 50%
Let the total number of people solicited by a charity be x
If 30% contributed 40$ each, their contribution will be 0.3x * 40 = 12x
Similarly, as 45% contributed 20$ each, their contribution will be 0.45x * 20 = 9x
The remainder of the people contributed 12$ each.
The contribution of the remaining 0.25x will be 0.25x * 12 = 3x
Since the total contribution is 12x+9x+3x = 24x,
the percentage of those who contributed 40$ each is \(\frac{12x}{24x}\) or 50%(Option E)