A man can walk a certain distance at a uniform speed in 100 days. How long will it take him to cover twice the distance at half the normal speed?
Answer: E
Earlier time = 100 days.
Distance is doubled and speed is reduced to half. ∴ time will become 2 × 2 i.e. 4 times.
Hence now it will take 100 × 4 = 400 days.