<PRE><B>Question 175451</B>
A passenger train travels 392 mi in the same time that it takes a freight
 train to travel 322 mi. If the passenger train travels 20 mi/h faster than
 the freight train, find the speed of each train.
;
Let s = speed of the freight
then
(s+20) = speed of the passenger train
:
Since the problems states the times are equal, write a time equation
Time = dist/speed
:
Pass time = freight time
 {{{392/((s+20))}}} = {{{322/s}}}
Cross multiply
392s = 322(s+20)
:
392s = 322s + 6440
:
392s - 322s = 6440
:
70s = 6440
s = {{{6440/70}}}
s = 92 mph is the freight
then
92 + 20 = 112 mph is the passenger train
:
:
Check solution by finding the times of each
392/112 = 3.5 hrs
322/92 = 3.5 hrs
</PRE>