Posted by **alicia** on Monday, February 7, 2011 at 4:27am.

i cannot seem to make this work. If two trains leave the station at the same time, one traveling north and the other traveling south. the express travels 14 mph faster than the local. after 3 hours they are 315 miles apart. what is the rate of each train.

this is what I figured:

r * t= d

y=x+14.

3x + 3y= 315

- math -
**Reiny**, Monday, February 7, 2011 at 10:15am
I used to make my students draw up a chart for these type of questions, having 3 columns for (D)istance, (R)ate, and (T)ime, and two rows for the different situations, in this case North and South

..........D....R.....T

north .. 3x .. x ... 3

south 3(x+14) x+14 .. 3

Now use the information that the sum

of the two distances is 315 to get

so 3x + 3(x+14) = 315

easy from there.

Why are you using 2 unknowns ?

Notice that if you subbed in your first equation into your second, you would get my equation.

## Answer This Question

## Related Questions

- math - Supppose two trains leave Holbrook, Arizona, at the same time, traveling ...
- Math - Two trains leave the same station at the same time, but are headed in ...
- math - 2 trains leave the same train station at the same time, one train travels...
- trig - two trains leave Kansas City at the same time. Train A is traveling due ...
- math - Two trains leave a station at 11:00am. One train travels north at a rate ...
- ALGEBRA - I need help with two problems to finish my assignment. #1 The length ...
- Algebra - Two trains leave Raleigh at the same time, one traveling north, the ...
- math - Two trains depart at the same time from the same station and travel in ...
- math - Two trains depart at the same time from the same station and travel in ...
- Algebra - Trains A and B are traveling in the same direction on parallel tracks...

More Related Questions