If 10 litres of an oil of Rs.50 per litres be mixed with 5 litres of another oil of Rs.66 per litre then what is the rate of mixed oil per litre? Pick one
A) rs . 49.17 B) rs . 51.03 C) rs . 54.17 D) rs . 55.33 E) none of the above

Rationale: "50 * 10 = 500 66 * 5 = 330 830 / 15 = 55.33 answer : d"
Answer: D