SOLUTION: My homework is on story problems and i just dont know how to set it up niether do my parents. Question: YOur aunt and uncle have been visiting at your home. Five minutes after

Algebra ->  Rational-functions -> SOLUTION: My homework is on story problems and i just dont know how to set it up niether do my parents. Question: YOur aunt and uncle have been visiting at your home. Five minutes after       Log On


   



Question 523656: My homework is on story problems and i just dont know how to set it up niether do my parents.
Question:
YOur aunt and uncle have been visiting at your home. Five minutes after they drive away, you realize that they forgot thier bags. You happen to know that they drive slowly, so you get in your car and drive to catch up to them. Your average speed is 10 mph faster than thier average speed,and you catch up with them in 25 minutes. How fast did you drive?
Verbal Model- Your speed = Their Speed + 10 mph
Your speed x Your time in hours = Their speed x Their speed in hours

Found 2 solutions by stanbon, MathTherapy:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
YOur aunt and uncle have been visiting at your home.
Five minutes after they drive away, you realize that they forgot thier bags.
----
You happen to know that they drive slowly, so you get in your car and drive to catch up to them.
-----
Your average speed is 10 mph faster than their average speed,and you catch up with them in 25 minutes.
--------
How fast did you drive?
----
"Your" DATA:
rate = r+10 mph ; time = 25 min = 5/12 hr ; distance = r*t = (5/12)(r+10) miles
===================
"Their" DATA:
rate = r mph ; time = 30 min = 1/2 hr ; distance = r*t = (1/2)r miles
--------
Equation:
your distance = their distance
(5/12)(r+10) = (1/2)r
---
Multiply thru by 12 to get:
5(r+10) = 6r
5r+50 = 6r
r = 50
r = 10 mph (Their driving rate)
r+10 = 20 mph (Your driving rate)
========================================
Cheers,
Stan H.
===========

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

My homework is on story problems and i just dont know how to set it up niether do my parents.
Question:
YOur aunt and uncle have been visiting at your home. Five minutes after they drive away, you realize that they forgot thier bags. You happen to know that they drive slowly, so you get in your car and drive to catch up to them. Your average speed is 10 mph faster than thier average speed,and you catch up with them in 25 minutes. How fast did you drive?
Verbal Model- Your speed = Their Speed + 10 mph
Your speed x Your time in hours = Their speed x Their speed in hour

Let my speed be S
Then my aunt and uncle’s speed = S - 10

Time I took to travel to meeting point = 25 minutes, or 5%2F12 hr
Time that my aunt and uncle took to travel to meeting point = 30 (5 + 25) mins, or ½ hr

Because distance I traveled = distance my aunt and uncle traveled, then:

%285%2F12%29%2AS+=+%281%2F2%29%2A%28S+-+10%29

%285S%2F12%29+=+%28S+-+10%29%2F2

12(S – 10) = 10S ------ Cross-multiplying

12S – 120 = 10S

2S = 120

S, or my speed = 120%2F2, or highlight_green%2860%29 mph

Send comments and “thank-yous” to “D” at MathMadEzy@aol.com