SOLUTION: A train travelled from A to B and back in a certain time at rate of 60 km/hr. But if the train had travelled from A to B at the rate of 80 km/hr and back from B to A at the rate o

Algebra ->  Test -> SOLUTION: A train travelled from A to B and back in a certain time at rate of 60 km/hr. But if the train had travelled from A to B at the rate of 80 km/hr and back from B to A at the rate o      Log On


   

Question 734373: A train travelled from A to B and back in a certain time at rate of 60 km/hr. But if the train had travelled from A to B at the rate of 80 km/hr and back from B to A at the rate of 40 km/hr it would take 2 hours longer. find the distance between A to B.
Found 2 solutions by lynnlo, ankor@dixie-net.com:
Answer by lynnlo(4176) About Me  (Show Source):
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A train traveled from A to B and back in a certain time at rate of 60 km/hr.
But if the train had traveled from A to B at the rate of 80 km/hr and back
from B to A at the rate of 40 km/hr it would take 2 hours longer.
find the distance between A to B.
:
let d = distance from A to B
let t = time for round trip at 60 km/hr
then
t = %282d%29%2F60
:
"But if the train had traveled from A to B at the rate of 80 km/hr and back from B to A at the rate of 40 km/hr it would take 2 hours longer. "
d%2F80 + d%2F40 = t + 2
Replace t with 2d/60
d%2F80 + d%2F40 = %282d%29%2F60 + 2
multiply by 240 to clear the denominators, resulting in:
3d + 6d = 4(2d) + 240(2)
9d = 8d + 480
9d - 8d = 480
d = 480 km from A to B
:
:
Confirm this solution by finding the times
960/60 = 16 hrs
and
480/80 = 6 hrs
480/40 = 12 hrs
-------------
total : 18 hr, 2 hrs more