SOLUTION: Please help me solve this question: If a car traveled 5kilometer an hour faster it would take one hour less to travel 210 km. what is the speed of the car and what time does it ta

Algebra ->  Coordinate Systems and Linear Equations -> SOLUTION: Please help me solve this question: If a car traveled 5kilometer an hour faster it would take one hour less to travel 210 km. what is the speed of the car and what time does it ta      Log On


   

Question 689340: Please help me solve this question:
If a car traveled 5kilometer an hour faster it would take one hour less to travel 210 km. what is the speed of the car and what time does it take?
Thank you,
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
If a car traveled 5kilometer an hour faster it would take one hour less to travel 210 km.
what is the speed of the car and what time does it take?
:
Let s = actual speed of the car
then
(s+5) = the faster speed
:
Write a time equation; time = dist/speed
:
Actual time - faster time = 1 hr
210%2Fs - 210%2F%28%28s%2B5%29%29 = 1
Get rid of the denominators, multiply by s(s+5), results
210(s+5) - 210s = s(s+5)
210s + 1050 - 210s = s^2 + 5s
Arrange as a quadratic equation
0 = s^2 + 5s - 1050
Factors to
(s+35)(s-30) = 0
The positive solution
s = 30 km/h is the actual speed
Find the time
210%2F30 = 7 hrs actual time
:
:
Confirm this by finding the time at the faster speed
210/35 = 6 hrs, 1 hr less