Question 18
Khánh has a collection of 30 stickers of various sizes. This morning, Châu visits and takes 10 stickers. The next day, Châu asks for 5 more Pokémon stickers and gives Khánh some other stickers. When Khánh counts again, the number of stickers is twice the original number. How many stickers did Châu give Khánh?
