A women travels from X to Y distance of 1000 miles in 10 hours. she returns to X in 4 hours. Find her average speed Choose the correct answer.
A) 300 mph	B) 150.2 mph	C) 142.8 mph	D) 200 mph	E) 111.01 mph

Rationale: speed from x to y = 1000 / 10 = 100 mph speed from y to x = 1000 / 4 = 250 mph average speed = 2 * 100 * 250 / 350 = 142.8 mph answer is c
Answer: C