Fox jeans regularly sell for $15 a pair and Pony jeans regularly sell for $18 a pair. During a sale these regular unit prices are discounted at different rates so that a total of $8.64 is saved by purchasing 5 pairs of jeans: 3 pairs of Fox jeans and 2 pairs of Pony jeans. If the sum of the two discount rates is 22 percent, what is the discount rate on Pony jeans?	Choose the most appropriate option
A) 8%	B) 10%	C) 11%	D) 12%	E) 14%
Let x be the discount on Pony jeans. Then 0.22-x is the discount on Fox jeans.   3(0.22-x)(15) + 2x(18) = 8.64   9.9 - 45x + 36x = 8.64   9x = 1.26   x = 0.14   The answer is 14%.
<result>E</result>
Fox jeans regularly sell for $15 a pair and Pony jeans regularly sell for $18 a pair. During a sale these regular unit prices are discounted at different rates so that a total of $8.64 is saved by purchasing 5 pairs of jeans: 3 pairs of Fox jeans and 2 pairs of Pony jeans. If the sum of the two discount rates is 22 percent, what is the discount rate on Pony jeans?