Question #f63a5

1 Answer
Oct 10, 2017

12 comic books.

Explanation:

Start by setting this up as an equation:

We know that he ends up with 12, so we can write

"stuff"=12
The trickier part comes in when we want to know what that "stuff" is.
He starts with x comic books, and then sells half of them so he now has 1/2 as many, or 1/2 x. After he halves them, he gains 6 more comic books, which brings us up to 1/2 x+6.

We know that 1/2 x+6 results in 12, so we can write the equation as:

1/2 x+6=12

Now, we solve for x.

Start with PEMDAS (parenthases, exponents, multiplication/division, addition/subtraction) and isolate x in the reverse order of operations. So, start with addition/subtraction.

Subtract 6 from both sides to get:

1/2 x cancel(+6-6)=12-6
or
1/2 x = 6

Now, we want to get rid of the fraction, so we need to multiply both sides by 2/1, because inverse (reciprocal) fractions cancel:

cancel(2/1 * 1/2) x=6*2/1
or
x=12

Strangely enough, he started and ended with the same amount!