while on a straight road...

[shibal]

while on a straight road, car X and car Y are traveling at different constant rates. If car X is now 1 mile ahead of car Y, how many minutes from now will car X be 2 miles ahead of car Y?

(1) Car X is traveling at 50 miles per hour and car Y is traveling 40 miles per hour

(2) 3 minutes ago car X was 0.5 miles ahead of car Y....

OA later....

[DeepakR]

1. Relative speed, S= 50-40 = 10 mph
Distance = 1 mile hence time taken to cover 1 mile, T= 1/10hr = 6 mins
Hence sufficient to find 2 miles = 12 mins. Now answer can be A or D

2. 3 mins it is 1/2 mile ahead hence
how many mins to cover 2 miles ? T= 12 mins
Hence B is also sufficient.

Hence answer is D.) both alone can answer the question.

- Deepak