SOLUTION: My homework problem:
If increase the average speed of a 189 mile trip by 12mph will make the same trip one hour shorter.What is the original average speed?
I think I have 2 e
Algebra.Com
Question 129394: My homework problem:
If increase the average speed of a 189 mile trip by 12mph will make the same trip one hour shorter.What is the original average speed?
I think I have 2 equations:
1) vt=189mph
2) v+12mph = 189mph/ (t-1h)
How do I solve for V? I tried substitution of 1) into 2) but got confused in how to solve for v in the next step. Thanks for your help. Jp
Answer by Fombitz(32388) (Show Source): You can put this solution on YOUR website!
Rate times time equals distance.
Your two equations are correct but watch the units.
It's 189 miles, not mph.
1.
2.
To solve you use one of the equations to get an expression for one of the variables in terms of the other and then substitute.
From 1,
Now substitute this value into 2,
Multiply both sides by t.
Use the FOIL method for the left hand side,
You can factor this equation into,
There are two solutions,
The first solution is,
The second solution is,
For your equation, t represents time.
A negative time does not make sense in this application.
You would use the positive answer for your solution.
Check your answer.
1.
2.
Your answer leads to a true statement, it's a good answer.
The original average speed is 42 mph.
RELATED QUESTIONS
Please help me solve this problem: A trip of 189 miles can take one hour less if gerald... (answered by ankor@dixie-net.com)
increasing the average speed of a car by 12 mph results in a 189 mile trip taking an hour (answered by jorel1380)
Average Speed, Each week you must make a 180-mile trip to pick up supplies for your... (answered by ewatrrr)
If the speed were increased by 10mph, a 420 mile trip wud take and hour less. how long... (answered by Nate)
If the speed were increased by 10mph, a 420-mile trip would take 1 hour less time. How... (answered by ankor@dixie-net.com)
A truck driver takes between 3.5 and 4 hours to make a 90 mile trip. The average speed in (answered by Matthebat14)
A man drive to a town at an average speed of 60 miles per hour. He returns by a road... (answered by ankor@dixie-net.com)
In order to make the 450-mile trip from Hudsonville to Chesterton, Morgana rode the bus.... (answered by solver91311)
A truck driver traveled at an average speed of 64 miles per hour on a 200-mile trip to... (answered by richwmiller)