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 $6 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 discounts rates is 18 percent, what is the discount rate on Pony jeans? Choose the most appropriate option:
A) 9%
B) 10%
C) 11%
D) 35%
E) 15%
You know that Fox jeans costs $15, and Pony jeans costs $18, you also know that 3 pairs of Fox jeans and 2 pairs of Pony jeans were purchased. So   3(15) = 45 - Fox   2(18) = 36 - Pony   The total discount discount is $6 and you are asked to find the percent discount of pony jeans,   so 45(18 - X)/100 + 36(X)/100 = 6 or 45*18 -45*x + 36*x =6*100 or 9x = -6*100 +45*18= 
<gadget id="calculator">-6*100 +45*18</gadget>
<output>210</output>
210/6= 
<gadget id="calculator">210/6</gadget>
<output>35</output>
35%   35%
<result>D</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 $6 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 discounts rates is 18 percent, what is the discount rate on Pony jeans?