First, subtract 24 - 14 to get how many books he had after he sold half of his collection and bought 14 more:
24 - 14 = 10
10 = number of books after he sold half of his collection.
Now, you need to multiply 10 x 2, because you need to find the original number of comic books:
10 x 2 = 20
He originally had 20 comic books.
An equation you could use for this question is:
2(24 - 14) = x. (X = number of comic books)
Hope this helps!!
~Kiwi