SOLUTION: Ryn left the museum and drove south. Gab left 3 hours later driving 42 km/h faster in an effort to catch up to him. After 2 hrs, Gab finally caught up. Find Ryn's average speed.

Algebra ->  Customizable Word Problem Solvers  -> Travel -> SOLUTION: Ryn left the museum and drove south. Gab left 3 hours later driving 42 km/h faster in an effort to catch up to him. After 2 hrs, Gab finally caught up. Find Ryn's average speed.       Log On

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Question 1026936: Ryn left the museum and drove south. Gab left 3 hours later driving 42 km/h faster in an effort to catch up to him. After 2 hrs, Gab finally caught up. Find Ryn's average speed.
Found 2 solutions by josmiceli, MathTherapy:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
What was Ryn's head start in km?
Let +s+ = Ryn's average speed
Ryn's head start = +s%2A3+ km
------------------------------
Start a stopwatch when Gab leaves
Let +d+ = distance in km that Gab travels
until Gab catches up with Ryn.
-------------------------------
Gab's equation:
(1) +d+=+%28+s+%2B+42+%29%2A2+
Ryn's equation:
(2) +d+-+s%2A3+=+s%2A2+
----------------------
Substitute (1) into (2)
(2) +%28+s+%2B+42+%29%2A2+-+s%2A3+=+s%2A2+
(2) +2s+%2B+84+-+3s+=+2s+
(2) +3s+=+84+
(2) +s+=+28+
Ryn's average speed is 28 km/hr
--------------------
check:
(1) +d+=+%28+s+%2B+42+%29%2A2+
(1) +d+=+%28+28+%2B+42+%29%2A2+
(1) +d+=+140+ km
and
(2) +d+-+s%2A3+=+s%2A2+
(2) +d+-+s%2A3+=+s%2A2+
(2) +d+=+5s+
(2) +d+=+5%2A28+
(2) +d+=+140+ km
OK

Answer by MathTherapy(10556) About Me  (Show Source):
You can put this solution on YOUR website!

Ryn left the museum and drove south. Gab left 3 hours later driving 42 km/h faster in an effort to catch up to him. After 2 hrs, Gab finally caught up. Find Ryn's average speed.
Let Ryn’s speed be S
Then Gab’s speed = S + 42
As Ryn drove for 5 (3 + 2) hours, and Gab drove for 2 hours, we get the following DISTANCE equation:
5S = 2(S + 42)
5S = 2S + 84
5S – 2S = 84
3S = 84
S, or Ryn’s speed = 84%2F3, or highlight_green%28matrix%281%2C2%2C+28%2C+%22km%2Fh%22%29%29