A couple who own an appliance store discover that if they advertise a sales discount of 10% on every item in the store, at the end of one month the number of total items sold increases 30%. Their gross income from sales for one month increases by what percent?	Select the correct option:
A) 9%  B) 11%  C) 13%  D) 15%  E) 17%
Let P be the original price and let x be the number of items sold originally.   The original income is P*x.   After the changes, the income is 0.9P*1.3x = 1.17*(P*x), an increase of 17%.   The answer is 17%.0.9 *1.3= 
<gadget id="calculator">0.9 *1.3</gadget>
<output>1.17</output>
1.17*(P*x), an increase of 17%.   The answer is 17%.
<result>E</result>
A couple who own an appliance store discover that if they advertise a sales discount of 10% on every item in the store, at the end of one month the number of total items sold increases 30%. Their gross income from sales for one month increases by what percent?