Two cars pass each other in opposite direction. How long would they take to be 500 km apart? I. The sum of their speeds is 135 km/hr. II. The difference of their speed is 25 km/hr.

• A. I alone sufficient while II alone not sufficient to answer
• B. II alone sufficient while I alone not sufficient to answer
• C. Either I or II alone sufficient to answer
• D. Both I and II are not sufficient to answer
• E. Both I and II are necessary to answer