Mary sold half of her comic books and then bought 8 more. she now has 18. how many did she begin with?

2 Answers
May 24, 2018

She had 20 books


If she bought 8 more and in total she have 18 before she buy those 8 books she had 10 so #10*2 = 20# because she sold half of her books that means she had double the amount of 10.

May 24, 2018



Work backwards from the final count.

Final count #->18#

This was after adding eight more #18-8=10#

This was after selling half the original amount

original amount #->2xx10=20#