<PRE><B>Question 982405</B>
.
distance=rate x time
Since distance is the same:
rate of express x 15 hours=rate of freight x 18 hours
rate of express=rate of freight + 15mph
Let F=rate of freight train:
.
(F+15mph)(15hrs)=F(18hrs)
15F+225=18F
225=3F
75mph=F ANSWER 1: The freight train travels at 75 mph.
Express=Freight + 15 mph=75mph+15mph=90mph
ANSWER 2: The express train travels at 90 mph.
.
CHECK:
(90mph)(15hrs)=(75mph)(18hrs)
1350 miles=1350 miles</PRE>