If 10 litres of an oil of Rs.50 per litres be mixed with 5 litres of another oil of Rs.67 per litre then what is the rate of mixed oil per litre?
Choose the correct option
A) rs . 49.17	B) rs . 51.03	C) rs . 54.17	D) rs . 55.66	E) none of the above

Rationale: "50 * 10 = 500 67 * 5 = 335 835 / 15 = 55.66 answer : d"
Answer: D