Problema Solution
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 provided by our tutors
let
v1 = Gabriella's average speed
v2 = Ryan's average speed
t1 = 2 hr the time of Gabriella's travel
t2 = time of Ryan's travel
Gabriella left three hours later driving 42 km/h faster in an effort to catch up to him:
v1 = v2 + 42
Gabriella left three hours later and after 2 hours finally caught up:
t1 = t2 - 3
t2 - 3 = 2
t2 = 2 + 3
t2 = 5 hr
since the both traveled the same distance and distance = speed*time we have
v1*t1 = v2*t2
2v1 = 5v2
by solving the system of equations:
v1 = v2 + 42
2v1 = 5v2
we find:
v1 = 70 mph
v2 = 28 mph
click here to see the step by step solution of the system of equations:
Ryan's average speed was 28 mph.