The radius of the wheel of a bus is 250 cms and the speed of the bus is 66 km/h, then the r.p.m. (revolutions per minutes)of the wheel is	Choose the correct choice from the following answers:
A) 70 B) 125 C) 300 D) 500 E) none of these

Rationale: "radius of the wheel of bus = 250 cm . then , circumference of wheel = 2 ï € r = 500 ï € = 1571.43440 cm distance covered by bus in 1 minute = 66 â  „ 60 ã — 1000 ã — 100 cms distance covered by one revolution of wheel = circumference of wheel = 1571.45 cm â ˆ ´ revolutions per minute = 6600000 / 60 ã — 1571.43 = 70 answer a"
Answer: A