A dessert recipe calls for 50% melted chocolate and 50% raspberry puree to make a particular sauce. A chef accidentally makes 15 cups of the sauce with 40% melted chocolate and 60% raspberry puree instead. How many cups of the sauce does he need to remove and replace with pure melted chocolate to make the sauce the proper 50% of each?  Choose the most appropriate option.
A) 1.5  B) 2.5  C) 3  D) 4.5  E) 5
we have 15 cups of sauce with 4040 choc and 6060 rasb   cups of choc = 0.4∗15=6   cups of rasb = 0.6∗15=9   now let say we removed x cup of original mix and replaced with x cups of choc.   therefore final number of cups of choc =6−0.4x+x   now this number of cup should be 50% of total = 15/2= 
<gadget id="calculator">15/2</gadget>
<output>15/2 = around 7.5</output>
7.5   therefore 6−0.4x+x=7.5   on solving x=2.5   ANSWER:2.5
<result>B</result>
A dessert recipe calls for 50% melted chocolate and 50% raspberry puree to make a particular sauce. A chef accidentally makes 15 cups of the sauce with 40% melted chocolate and 60% raspberry puree instead. How many cups of the sauce does he need to remove and replace with pure melted chocolate to make the sauce the proper 50% of each?