orangefeet said:
So theres no tips just to understand whats behind it.....there has to be some more tips.
I'm really surprised that no one has suggested that you DRAW a diagram for each of your "various types" of distance problems. If you do that, then "what to do" to write an equation becomes fairly obvious.
I'll just give you ONE example....
One car leaves Omaha at noon, heading east at 55 mph.
A second car leaves Omaha at 1 p.m., also heading east at 70 mph.
When does the second car catch up with the first car?
Let x = time traveled by first car
The second car leaves Omaha 1 hour AFTER the first car, so it would travel x - 1 hours when it catches up with the first car.
Here's the diagram I would draw:
For the first car:
O---------------------------------------------> C
OC = 55x
For the second car:
O--------------------------------------------->C
OC = 65 * (x - 1)
When the second car catches up with the first car, they will have traveled the same distance, right?
So...
OC (for first car) = OC (for second car)
55x = 65(x - 1)
There's your equation...and you can solve it for x, the time traveled by the first car.
There's an old saying: "a picture is worth a thousand words"
Drawing a "picture" of what happens in one of these kinds of problems is CERTAINLY worth a thousand words...and you don't have to memorize any formulas....
Please THINK about what the problem says.
