Step 1:
Given data
Let c represent the number of comic books with which she begin.
When sh sold half of her comic books
Then, she will be left with
When she bought 15 more, she now has 30.
15 more, mean you add 15 to c/2 then equate it to 30.
Next, write an equation.
Step 2:
Solve the linear equation to find the value of c.
Step 3:
Final answer