A merchant has 100 lbs of sugar, part of which he sells at 7% profit and the rest at 15% profit. He gains 10 % on the whole. Find how much is sold at 7% profit?  Choose the correct choice.
A) 70 lbs	B) 40 lbs	C) 30 lbs	D) 50 lbs	E) 63 lbs
These types ofweighted averagequestions can be solved in a variety of ways, so you can choose whichever method you find easiest/fastest. Here's another variation on the Weighted Average Formula:   A = # of pounds sold at 7% profit   B = # of pounds sold at 15% profit   A+B = 100 pounds   (.07A + .15B)/(A+B) = .10   .07A + .15B = .1A + .1B   .05B = .03A   5B = 3A   5/3 = A/B   So, for every 5 pounds of A, we have 3 pounds of B.   With 100 pounds total, we have 63 pounds of A and 37 pounds of B.   option 63 lbs
<result>E</result>
A merchant has 100 lbs of sugar, part of which he sells at 7% profit and the rest at 15% profit. He gains 10 % on the whole. Find how much is sold at 7% profit?