Walking at 3/4 of his usual place, a man reaches his office 20 minute late. Find his usual time?
Choose the correct choice from the following choices
A) 2 hr	B) 1 hr	C) 3 hr	D) 1.5 hr	E) 2.5 hr

Rationale: let the original speed be s and time be t if new speed = s ã — 3 / 4 , then new time would be t ã — 4 / 3 ( d = st = constant ) . given , 3 t / 4 â ˆ ’ t = 20 t / 3 â ‡ ’ t = 60 minutes = 1 hour answer : a
Answer: A