SOLUTION: A train is going at 1/4 of its usual speed and it take an extra 45 minutes to reach its destination. Find its usual time to cover the same distance.

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Question 1187160: A train is going at 1/4 of its usual speed and it take an extra 45 minutes to reach its destination. Find its usual time to cover the same distance.
Found 2 solutions by ankor@dixie-net.com, ikleyn:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
A train is going at 1/4 of its usual speed and it take an extra 45 minutes to reach its destination.
Find its usual time to cover the same distance.
;
let s = the normal speed
then
.25s = the actual speed
and
t = normal time
Change 45 min = .75 hrs
:
write a distance equation, dist = speed*time
st = .25s(t +.75)
st = .25st + .1875s
simplify, divide by s
t = .25t + .1875
t - .25t = .1875
.75t = .1875
t = .1875/.75
t = .25 hrs or 15 min is the normal time
:

Answer by ikleyn(52786) About Me  (Show Source):
You can put this solution on YOUR website!
.
A train is going at 1/4 of its usual speed and it take an extra 45 minutes to reach its destination.
Find its usual time to cover the same distance.
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Let t be the usual time, in minutes.


When the train moves at 1/4 of the usual speed, the travel time is 4 times the usual time, i.e. 4t minutes.


We are given  4t - t = 45 minutes,  which gives  3t = 45 minutes  and  t = 45/3 = 15 minutes.


ANSWER.  Usual time is 15 minutes.

Solved.