Ryan left the science museum and drove south. Gabriella left three hours later driving 42 km/h faster in an effort to catch up to him. After two hours Gabriella finally caught up. Find Ryan's average speed.

Answer:Ryan's average speed is 28km/h

Step-by-step explanation:

Let x represent the average speed of Ryan. If Gabriella drove 42 km/h faster in an effort to catch up to Ryan, It means that Gabriella's speed is x + 42

At the time that Gabriella finally caught up with Ryan, both of them would have travelled equal distances.

Distance travelled = speed * time

time = distance / speed.

If Gabriella left three hours later and caught up with Ryan in two hours time, it means that total time spent by Ryan is 3+2 = 5 hours

Total distance covered by Ryan would be

x * 5 = 5x km

Total distance covered by Gabriella would be

2 (x + 42) = 2x + 84

Since both of them cover equal distances, therefore,

5x = 2x + 84

5x - 2x = 84

3x = 84

x = 84/3 = 28 km/h