If Sheila has 30 stickers left after giving away some, how many did she start with?

To determine how many stickers Sheila started with, we need to consider the context of the problem. The question states that after giving away some stickers, she has 30 left. The choices presented suggest that we are looking for a scenario where if Sheila had given some away, she still has these 30 remaining.

The better choice would be to relate the number of stickers she started with to a scenario where giving away some would leave her with 30. For instance, if she started with 180 stickers and gave away a certain number, it is plausible that 30 could remain as a result of giving away a significant portion.

By analyzing the other quantities, if Sheila had started with 90 stickers or 120 stickers, the amount given away to still end up with 30 would not seem reasonable as it implies giving away more than she originally had in the case of 90, or insufficient to leave her with 30 in the case of 120.

Choosing 180 allows for many combinations because she could have given away a range of stickers (from just a few up to 150, leaving her with exactly 30). Thus, starting with 180 stickers accommodates the condition of having 30 left after giving away some, making it the