Question

Joan sold half of her comic books and then bought 8 more. She now has 15. How many did she begin with?

Answer 1

`14`

Explanation:

Let's construct an equation for the question and solve it

Let the number of comic books that Joan had in the beginning is `x`

In the start she sold half her books (so,multiply by `1/2`)

`color(red)(x*1/2`

Next, she bought `8` more books (so,add `8`)

`color(red)(x*1/2+8`

At the last she has `15` books (so,let the equation equal `15`)

`color(red)(x*1/2+8=15`

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Now let's solve the completed equation

`rarrx*1/2+8=15`

Subtract `8` both sides

`rarrx*1/2+cancel8-cancelcolor(violet)(8)=15-color(violet)(8)`

`rarrx*1/2=7`

Multiply both sides by `2`

`rarrx*1/cancel2*cancelcolor(violet)(2)=7*color(violet)(2)`

`color(green)(rArrx=14`

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So Joan started with `14` comic books

Hope this helps !...

:)