Daria is raising money for a new vacuum cleaner. So far, she has collected $20 in her piggy bank and has decided to put $10 in it each week. If the vacuum cleaner costs $120, how many weeks will it take her to raise enough money to cover this expense?
The vacuum cleaner costs $120, so Daria needs 120 - 20 = $<<120-20=100>>100 more.
Daria will need 100 / 10 = <<100/10=10>>10 more weeks, to be able to buy the vacuum cleaner.
#### 10