Algebra word problem formulas

Question

A car passes point A going 60 kph. Fifteen minutes later a second car going in the same direction passes point A going 80 kph. Assuming that both cars are maintaining a constant speed and continue on the same highwa

 

A - how long will it be before the second car catches up to the first car?

B - How far from point A will the two cars be when the second car catches up to the first car?

Answer 1

Distance = Speed*Time, and Time = Distance/Speed.  When the second car reaches point A, the first car has traveled (60 kph*0.25 hours) = 15 km

 

A - The second car is going 20 kph faster; it can close the 15 km gap in 15 km/20 kph = 0.75 hours.

 

B - In 0.75 hours, the second car will travel 80 kph*0.75 hours = 60 km