Question 149707

Distance(d) equals Rate(r) times Time(t) or d=rt;  r=d/t and t=d/r

Let r=rate of the local train
Then 2r=rate of the express

Time of local train=50/r
Time of express train=50/2r

Now we are basically told the following:
(50/r)-1=50/2r  multiply each side by 2r
100-2r=50  subtract 100 from each side
100-100-2r=50-100  collect like terms

-2r=-50  divide each side by -2
r=25 mph-------------speed of local
2r=2*25=50 mph--------------speed of express

CK
(50/25)-1=50/50
1=1


Hope this helps---ptaylor