Question 259567
Ryan left the science museum going south. 
Gabriel left 3 hours later riding 42 km per hour faster than Ryan.
 After 2 hours Gabriel caught up to Ryan.
 Find Ryan's average speed.
:
Let s = Ryan's average speed
then
(s+42) = Gabriel's speed
:
A couple useful facts
R's travel time = 5 hrs
G's travel time = 2 hrs
When G catch R, they will have traveled he same distance
:
Write a distance equation; dist = speed * time
:
R's dist = G's dist
5s = 2(s+42)
5s = 2s + 84
5s - 2s = 84
3s = 84
s = {{{84/3}}}
s = 28 km/hr is Ryan's speed
:
:
Check solution by ensuring that they did travel the same dist
5(28) = 140 km
2(28+42) = 140 km