SOLUTION: A train set off on a journey of 800 miles. Things went well for a while but then it ran into snow and was forced to stop for 2 hours at a station 200 miles from the starting point.

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Question 411875: A train set off on a journey of 800 miles. Things went well for a while but then it ran into snow and was forced to stop for 2 hours at a station 200 miles from the starting point. Once the trip was resumed, there was still so much snow on the tracks than its average speed for the remainder of the journey was reduced by 25 miles per hour compared to first leg. If train arrived at its destination 18 hours after it started, what was its average speed on the first leg of the trip?
Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website!
First leg speed be x mph
second leg speed = x-25 mph
...
first leg distance = 200 miles
second leg distance = 600 miles
..
total time = 18-2=16 hours
time first leg +time second eg = 16
200/x + (600/(x-25) =16
LCD = x(x-25)
multiply bth sides by x(x-25)
200(x-25)+600x=16(x(x-25))
200x-5000+600x=16x^2-400x
16x^2-1200x+5000=0
2x^2-150x+625=0
solve by using quadratic formula
a=2 , b =-150 , c =625.
b^2-4ac=17500

speed = 70.6 mph

x2= 4.4 mph This is not possible