54*10 = 540
66*5 = 330
870/15 = 58
If 10 litres of an oil of Rs.54 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?
Options:
(a) Rs.49.17
(b) Rs.58
(c) Rs.54.17
(d) Rs.55.33
(e) None of the above