Robin mixes two liquids, one blue in coloUr and other red in colour in the ratio 2:3 and sells the mixture at the rate of $20 per liter, thereby making a 25% profit on his outlay. The blue liquid costs Robin $5 per litre lesser than the red liquid. How much does a liter of red liquid cost?  Choose the most appropriate option: A) 12 B) 13 C) 14 D) 15 E) 16
Let x be the required cost per litre of red paint.   Take 5 litres of this mixture.   Sold at 100 with a profit of 1/4th of total cost. So, total cost will be 1/5th less than 100; total cost = 80.   2(x-5) + 3(x) = 80   x = 14   Answer is 14
<result>C</result>
Robin mixes two liquids, one blue in coloUr and other red in colour in the ratio 2:3 and sells the mixture at the rate of $20 per liter, thereby making a 25% profit on his outlay. The blue liquid costs Robin $5 per litre lesser than the red liquid. How much does a liter of red liquid cost?