<human>:  Trevor is a comic book illustrator. In the past three months, he has drawn 220 pages of the comic. The comic he illustrates releases a new issue once a month. The first and second months’ issues were the same number of pages, but the third month’s issue was four pages longer than either of the others. How many pages was the first issue of the comic?
<bot>: Define a variable ** Let P be the number of pages of the first issue of the comic.
How many pages are the first and second issues? ** The second issue is the same number of pages, so the first and second issues are P + P = 2P pages.
How many pages is the third issue? ** The third issue is 4 pages longer, so it is P + 4 pages.
How many pages are the first, second, and third issues? ** All three issues are 2P + P + 4 = 3P + 4 = 220 pages long.
How many pages are the first, second, and third issues? ** Thus, 3P = 220 - 4 = 216 pages.
How many pages was the first issue of the comic? ** Therefore, the first issue of the comic was P = 216 / 3 = <<216/3=72>>72 pages.
#### 72