Using Charts to Problem Solve NEW

I've been having trouble with this homework, I took all the notes during class and asked all my friends, but I still can't solve these problems. Here's an example of one that I've tried and failed doing.

2. Find the number of round-trip commuter rail tickets sold.
(1) Thirty times as many round-trip tickets as 12-ride tickets were sold.
(2) The total number of tickets sold represented 1440 rides.

Here they give you a chart which looks like this:
So first off, I let:

n: The number of 12-ride tickets sold

Then I proceeded to fill in the chart, and it looks like this:
Now we have to solve how many round trip tickets were sold, so I set up my equation...

12n = 2(1440 - n)

12n = 2880 - 2n
+2n. . . . . . .+2n
14n = 2880

n = 205 (approximation)

And that isn't the correct answer, at least I don't think it is, because it doesn't seem to work out. I think that I may have messed up with setting up the equation, and it should be maybe:

12n + 2(1440 - n) = ?

But, I tried that and I also didn't get something correct. It also may be something to do with "(1) Thirty times as many round-trip tickets as 12-ride tickets were sold."

And that wasn't anywhere in my equation, but I don't know where to put it or how. All of our notes have questions similar, but they are more simple and don't have the use of variables as much, or when they do it is much easier.

Help!

Re: Using Charts to Problem Solve

I don't follow your chart; it should look like this:


Then equation is:
2(30n) + 12n = 1440

Solve for n

72n=1440, so n = 20?

Oh, thanks, it works! I checked it. I guess my graph was wrong, thanks! I took my notes down wrong

Why are you solving for n? I though you were looking for the round trip tickets.