A charity group decides to do a yard sale.  10 people donate 5 boxes of stuff each.  They also have 10 boxes of stuff already.  They can fit 2 boxes worth of stuff per table.  If they already own 15 tables, how many new tables do they need?
There were 10*5=<<10*5=50>>50 donated boxes
So they have a total of 50+10=<<50+10=60>>60 boxes
So they need a total of 60/2=<<60/2=30>>30 tables
That means they need 30-15=<<30-15=15>>15 tables
#### 15
<|Human|>

A charity group decides to do a yard sale.  10 people donate 5 boxes of stuff each.  They also have 10 boxes of stuff already.  They can fit 2 boxes worth of stuff per table.  If they already own 15 tables, how many new tables do they need?

<|Assistant|>

There were 10*5=<<10*5=50>>50 donated boxes
So they have a total of 50+10=<<50+10=60>>60 boxes
So they need a total of 60/2=<<60/2=30>>30 tables
That means they need 30-15=<<30-15=15>>15 tables
#### 15