SOLUTION: two railway stations are at a distance of 98 km from each other.one train cover this distance in 40 minutes less than the other.the speed of the first train is 12 km/h faster than

Algebra ->  Equations -> SOLUTION: two railway stations are at a distance of 98 km from each other.one train cover this distance in 40 minutes less than the other.the speed of the first train is 12 km/h faster than       Log On


   

Question 747202: two railway stations are at a distance of 98 km from each other.one train cover this distance in 40 minutes less than the other.the speed of the first train is 12 km/h faster than than the second.determine the speeds of both the trains.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
two railway stations are at a distance of 98 km from each other.
one train cover this distance in 40 minutes less than the other.
the speed of the first train is 12 km/h faster than than the second.
determine the speeds of both the trains.
:
Let s = speed of the slower train
then
(s+12) = speed of the faster train
:
Change 40 min to 2/3 hr
:
Write a time equation; time = dist/speed
:
slow train time - fast train time = 40 min
98%2Fs - 98%2F%28%28s%2B12%29%29 = 2%2F3
multiply by 3s(s+12), resulting in:
98(3(s+12)) - 98(3s) = 2s(s+12)
294s + 3528 - 294s = 2s^2 + 24s
a quadratic equation from this
2s^2 + 24s - 3528 = 0
simplify, divide by 2:
s^2 + 12s - 1764 = 0
solve this using the quadratic formula, I got about 36.4 mph for the slow train