A car dealer purchased new cars at 80% of their list price and sold them for 90% of their list price. What is his percent gain? Choices: A) 11 B) 12.5 C) 15 D) 16 E) 20
Cost = 80% of List Price = .8*L
Sale = 90% of List Price = .9*L
Gain Ratio = (Sale - Cost) / Cost = (.9*L - .8*L) / .8*L = .1*L / .8*L = .125
Gain Percent = 100 * Gain Ratio = 100 * .125= 
<gadget id="calculator">100 * .125</gadget>
<output>12.5</output>
12.5%= Answer 12.5
<result>B</result>
A car dealer purchased new cars at 80% of their list price and sold them for 90% of their list price. What is his percent gain?