Choose the correct answer. average speed of car 1 = 35 mph. average speed of car 2 = 55 mph. time elapsed between start of car 1 and start of car 2 = 18 minutes. how long before car 2 overtakes car 1? hour.

If we let x be the number of hours before Car 2 overtakes Car 1. The total time for Car 1 is x hours and 18 minutes. The distance they should cover should just be equal,
                           (35)(x+18/60) = 55x
The value of x from the equation is given above 0.525 hours or equal to 31.5 minutes.