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 20%. Their gross income from sales for one month increases by what percent?  Choose the correct answer:
A) 2%
B) 4%
C) 5%
D) 8%
E) 12%
Let List price of an item = 100   8%iscount on each item = 10%   8%iscounted price of an item = .9*100= 
<gadget id="calculator">.9*100</gadget>
<output>90</output>
90   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 20%   Originally if 10 items were sold in a month , with the new discount 12 items will be sold   Original revenue= No of items* Price of an item = 10 * 100= 
<gadget id="calculator">10 * 100</gadget>
<output>1_000</output>
1000   New revenue= 12 * 90= 
<gadget id="calculator">12 * 90</gadget>
<output>1_080</output>
1080   Increase in gross income= 1080 - 1000= 
<gadget id="calculator">1080 - 1000</gadget>
<output>80</output>
80   % increase in gross revenue= 80/1000 * 100= 
<gadget id="calculator">80/1000 * 100</gadget>
<output>8</output>
8%   Answer 8%
<result>D</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 20%. Their gross income from sales for one month increases by what percent?