Vincen wrote:Car P and car Q competed in the same 300-kilometer race. What was the average speed of car P?

(1) Car P completed the race in 3 hours and 40 minutes.

(2) Car Q, at an average speed of 100 kilometers per hour, completed the race 40 minutes before car P crossed the finish line.

The OA is D.

Experts, may you give me a detailed explanation here? I don't know why each statement alone is sufficient.

Speed = Distance / Time = 300/time

If we get the time in which car P completed the race, we get the answer.

(1) Car P completed the race in 3 hours and 40 minutes.

Sufficient.

(2) Car Q, at an average speed of 100 kilometers per hour, completed the race 40 minutes before car P crossed the finish line.

Time taken by car Q to complete the race = 300 kilometers / 100 kilometers per hour = 3 hours

Thus, taken by car P to complete the race = 3 hours + 40 minutes

Sufficient.

The correct answer: D

Hope this helps!

-Jay

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