A women purchased 3 towels @ Rs.100 each, 5 towels @ Rs.150 each and two towels at a certain rate which is now slipped off from his memory. But she remembers that the average price of the towels was Rs.155. Find the unknown rate of two towels? Choose the correct choice from the following options:
A) 400 B) 450 C) 500 D) 550 E) 600

Rationale: 10 * 155 = 1550 3 * 100 + 5 * 150 = 1050 1550 – 1050 = 500 c
Answer: C