<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?
<bot>: How many boxes were donated? ** There were 10*5=<<10*5=50>>50 donated boxes
How many boxes do they have? ** So they have a total of 50+10=<<50+10=60>>60 boxes
How many new tables do they need? ** So they need a total of 60/2=<<60/2=30>>30 tables
How many new tables do they need? ** That means they need 30-15=<<30-15=15>>15 tables
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