julie started with 20 pieces of gum and gave away x pieces. Karen started with 35 pieces of gum and gave away twice as many as julie did. How many pieces of gum did julie give away if they had the same number of pieces of gum?

15

Step-by-step explanation:

If you replace each answer choice with the varibale, (x) then 15 would be the only choice that fits properly.

Equation:

20-x = 35 - (2x)

when replacing 15 with x this is your new equation ...

20-15 = 35 - (2x15)

5 = 35-30

5=5