math help

[franks2089]

At noon a train leaves bridgton heading east at 90 mph to cogsville, 450 miles away. At 12:15 a train leaves cogsville heading to bridgton at 100 mph. At one time will they pass?

[Hookem]

2:30 i think

[HCrum05]

Just tell your teacher that they don't pass, they crash.

[franks2089]

2:30 i think
can you show me how you got that, because I checked it and that works but I have to show work for it.

[Hookem]

can you show me how you got that, because I checked it and that works but I have to show work for it.
used my brain lol... i dont know seriusly, what class is this in? Alegebra 2? Calculas?

[RockStar]

Let train 1 position = x1 where x1 is a function of time, t (Bridgton train)
Let train 2 position = x2, also a function of time, t in hours (Cogsville)

When the trains meet, x1=x2

So, develop the functions for x1 and x2

Assing Bridgton with position x = 0, Cogsville position x = 450.

so:

x1 = 0 + 90*t
x2 = 450 - 100*(t-0.25) {remember, this train left 1/4 hour later}

These functions evaluated for any real value of t in hours give you the distance away from Bridgton in miles

Set the two functions of t equal to each other and do your own stinking algebra!

I think you'll find that 2:30 is correct.

[franks2089]

Why was a question so simple needed to be asked here? 2:30 is the right answer. Done simply in my head, because it was so simple that it works out nicely:

450/2= 225

90mph @ 2.5 hours = 225
100mph @ 2.5-2.25 (half hour later) hours = 225

You don't even need to know alegebra to do this. I guess it must be the begining of school so they give you easy stuff to get you thinking. What class is this? Alegbra 1?
Algebra 2 but we are reviewing stuff from Algebra 1. I have always had trouble with word problems and setting up the equations.

[enjoi]

Do your own homework please.