SOLUTION: A motorist traveled from Town A to Town B. After traveling one third of the distance for the journey at an average speed of 45 km/h, he continued to travel another 480 km to reach

Algebra.Com
Question 1030976: A motorist traveled from Town A to Town B. After traveling one third of the distance for the journey at an average speed of 45 km/h, he continued to travel another 480 km to reach Town B. If his average speed for the entire journey was 54 km/h, what was his average speed for at least two thirds of the distance?
Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!
A motorist traveled from Town A to Town B.
After traveling one third of the distance for the journey at an average speed of 45 km/h, he continued to travel another 480 km to reach Town B.
If his average speed for the entire journey was 54 km/h, what was his average speed for at last two thirds of the distance?
:
From the information given we know the first third distance was half the distance of the last two thirds: 480/2 = 240km
The total dist: 240 + 480 = 720km
:
let s = speed for the last 2/3 dist
:
Write a time equation; time = dist/speed
:
Time at 45 + time at s = total time
+ =
multiply by the least common denominator, 270s
270s* + 270s* = 270s*
Cancel the denominators
6s(240) + 270(480) = 5s(720)
1440s + 129600 = 3600s
129600 = 3600s - 1440s
129600 = 2160s
s = 129600/2160
s = 60 km/hr for final 2/3 of the trip
:
;
See if that checks out
+ =
5.33 + 8 = 13.33 hrs

RELATED QUESTIONS

A motorist traveled from Town A to Town B. After traveling 13 of the distance for [4] the (answered by ankor@dixie-net.com)
A motorist traveled from Town A to Town B. After traveling 1/3 of the distance for the... (answered by TimothyLamb)
a motorist travels from town A to town B at an average speed of 56km/h on his return... (answered by josgarithmetic)
a motorist travels from town A to town B at an average speed of 56km/h on his return... (answered by josgarithmetic)
A motorist traveled along a straight road from Town A to Town B at 70 km/h. A... (answered by ankor@dixie-net.com)
A motorist travelled from town x to Town Y. After travelling for 1.5hour, he passed a... (answered by mananth)
A motorist traveled along a straight road from town A to town Bar 70 km/h. A motorcyclist (answered by ikleyn)
A motorist travelled from town X to town Y at an average speed of 90 km/h. after... (answered by ankor@dixie-net.com)
A man travels from Town A to Town B at an average speed of 4 km and from Town B to Town A (answered by Alan3354,greenestamps)