SOLUTION: A train averaged 80 km/h for the first half of its trip. How fast must it travel for the second half of the trip in order to average 96 km/h for the whole trip?
The answer is su
Algebra.Com
Question 112984This question is from textbook Algebra and Trigonometry Structure and Method Book 2
: A train averaged 80 km/h for the first half of its trip. How fast must it travel for the second half of the trip in order to average 96 km/h for the whole trip?
The answer is supposedly 120 km/h, but no matter what I do I get 112 km/h!
Help would be greatly appreciated. (:
This question is from textbook Algebra and Trigonometry Structure and Method Book 2
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
Let's let x = the speed for the second half of the trip. So should be the average for the the whole trip. Now we can write:
So let's solve for x:
Seems you are right with your 112km/hr answer. I'm not sure where you got the 120 answer, but it is clearly incorrect. If you got it from the answers in the back of your textbook, it could still be wrong. Wouldn't be the first math book I've seen with errors in it.
Hope this helps.
John
RELATED QUESTIONS
A train averaged 80 km/h for the first half of its trip. How fast must it travel for the (answered by josmiceli,jojo14344)
In the first half (distance) of a trip, a truck travels at a speed of 40 km/hr. How fast... (answered by ankor@dixie-net.com)
Peggy drives to town at a rate of 40 km/h. How fast must she drive in order to average 80 (answered by ikleyn,Alan3354)
Peggy drives to town at a rate of 40 km/h. How fast must she drive BACK in order to... (answered by Alan3354,ikleyn)
On a 100km track a train travells the first 30km at a uniform speed of 30km/h . How fast... (answered by Fombitz)
A train averaged 120 km/h for the first two thirds of a trip and 100 km/h for the whole... (answered by amoresroy,robertb)
A passenger train making a 240 km trip traveled the first 120 km at 75 km/h. At what... (answered by ewatrrr)
A car averaged 30 MPH for the first mile of a 2 mile trip. How fast would it have to... (answered by ankor@dixie-net.com)
Your average speed on the first half of a car trip is 70.0 km/h. How fast do you have to... (answered by stanbon,Edwin McCravy)