At a florist shop on a certain day, all corsages sold for either $20 or $30. If 10 of the corsages that sold for $30 had instead sold for $20, then the store's revenue from corsages that day would have been reduced by 20 percent. What was the store's actual revenue from corsages that day?  Choose the correct option:  A) $200  B) $400  C) $500  D) $800  E) $1000
Let, No. of corsages @ $20 = x, no. of corsages @ $30 = y and revenue= r   so, 20x+30y=r.........(1)   Now,   Given the situation, 20(x+10) + 30(y-10)= r-.2r   =&gt; 20x+200+30y-300 = .8r   =&gt; 20x+30y = .8r+100............(2)   so, r = .8r+100   =&gt; r = 500   The answer is $500.
<result>C</result>
At a florist shop on a certain day, all corsages sold for either $20 or $30. If 10 of the corsages that sold for $30 had instead sold for $20, then the store's revenue from corsages that day would have been reduced by 20 percent. What was the store's actual revenue from corsages that day?