<PRE><B>Question 917112</B>
The speed of an Amtrak passenger train is 12 mph faster than the speed of a Central Railway freight train. the passenger train travels 400 miles in the same time it takes the freight train to travel 330 miles. Find the speed of each train.
:
s = speed of the freight
then
(s+12) = speed of the pass train
:
Write a time equation; time = dist/speed
:
{{{330/s}}} = {{{400/((s+12))}}}
cross multiply
400s = 330(s+12)
400s = 330s + 3960
400s - 330s = 3960
s = 3960/70
s = 56.57 mph is the freight
then, obviously, 68.57 mph is pass train
:
:
Confirm this, find the time for each, should be equal
400/68.57 = 5.83 hrs
330/56.57 = 5.83 hrs</PRE>