SOLUTION: Emily drove 240 miles to see her parents for Thanksgiving. On the return trip, she drove 20 mph slower due to bad weather, so she made the return trip in 2 hours more time. What wa

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Question 1060203: Emily drove 240 miles to see her parents for Thanksgiving. On the return trip, she drove 20 mph slower due to bad weather, so she made the return trip in 2 hours more time. What was her speed on the way to her parents' home.
I am just confused on how to find the equation for the problem, once I have the equation I can solve the problem.
Found 3 solutions by ikleyn, josmiceli, MathTherapy:
Answer by ikleyn(52847) About Me  (Show Source):
You can put this solution on YOUR website!
.
Emily drove 240 miles to see her parents for Thanksgiving. On the return trip, she drove 20 mph slower due to bad weather,
so she made the return trip in 2 hours more time. What was her speed on the way to her parents' home.
I am just confused on how to find the equation for the problem, once I have the equation I can solve the problem.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

The equation is

240%2F%28r-20%29+-+240%2Fr = 2.

where "r" is the speed on the way "to there", (r-20) is the speed on the way back.

240%2Fr is the time to get "there".

240%2F%28r-20%29 is the time on the way back.


Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
It sounds like +240+ mi is the one-way distance
Let +s+ = her speed in mi/hr going to parent's house
Let +t+ = her time in hrs going to parent's house
---------------------------------------------------
Going to parent's house:
(1) +240+=+s%2At+
Returning from parent's house:
(2) +240+=+%28+s+-+20+%29%2A%28+t+%2B+2+%29+
-------------------------------
It's all yours
hint: solve for +t+ in (1), plug that into (2)
then solve for +s+

Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!
Emily drove 240 miles to see her parents for Thanksgiving. On the return trip, she drove 20 mph slower due to bad weather, so she made the return trip in 2 hours more time. What was her speed on the way to her parents' home.
I am just confused on how to find the equation for the problem, once I have the equation I can solve the problem.
Let speed on way to parents’ house be S

Then speed on return trip = S – 20

Time taken to travel to parents’ house: 240%2FS

Time taken on return trip: 240%2F%28S+-+20%29

Since the return trip took 2 hours longer, we get the following TIME equation: highlight_green%28240%2FS+=+240%2F%28S+-+20%29+-+2%29

FYI: You don't have to calculate time! It's not necessary since you're not asked to find the time spent on either trip-leg.