A feed store sells two varieties of birdseed: Brand A, which is 60% millet and 40% sunflower, and Brand B, which is 65% millet and 35% safflower. If a customer purchases a mix of the two types of birdseed that is 50% millet, what percent of the mix is Brand A?  Choose one
A) 40%
B) 60%
C) 50 %
D) 45 %
E) 55 %
Yes there is a simple method :   Consider the following method   Brand A : 60% millet and 40% sunflower   Brand B : 65% millet and 35% safflower   Mix : 50% millet   Here the weighted average is 50%,   Now Brand A has 60% millet, which is 10% more than the weighted average of mix = + 0.10 A --------------- I   Similarly, Brand B has 65 % millet, which is 15 % more than the weighted average of mix = + 0.15 B ------------ II   Now, both Brand A and Brand B are combined to give a 50% mix containing millet, so equate I and II   implies, 0.10 A = 0.15 B   Therefore A/B = 0.15/0.10 = 3/2   A : B : (A + B) = 3 : 2 : (3+2) = 3 : 2 : 5   We have to find, percent of the mix is Brand A i.e. A : (A + 60%) = 3 : 5 = (3 / 5) * 100= 
<gadget id="calculator">(3 / 5) * 100</gadget>
<output>60</output>
60 %   Here is a pictorial representation :   60%rand A= 60%------------------------10% or 0.10 above average, A times-----------------Total above = + 0.10 A   ----------------------------------------------------------------------------------------Average = 50% or 0.50   60%rand 60% = 65 %--------------------------15% or 0.15 above average, 60% times-----------------Total above = + 0.15 60%   Since the amount below the average has to equal the average above the average; therefore,   0.10 A = 0.15 60%   A/60% = 3/2   A:60%: Total = 3:2:5   Therefore   A/Total = 3:5 = 60 %   Answer: 60%
<result>B</result>
A feed store sells two varieties of birdseed: Brand A, which is 60% millet and 40% sunflower, and Brand B, which is 65% millet and 35% safflower. If a customer purchases a mix of the two types of birdseed that is 50% millet, what percent of the mix is Brand A?