human
A set of 7 spoons costs $21. If each spoon would be sold separately, how much would 5 spoons cost?
assistant
How much does one spoon from the set cost? ** A set of 7 spoons costs $21, so one spoon from the set costs 21 / 7 = $<<21/7=3>>3.
How much would 5 spoons cost if sold separately? ** So if sold separately, 5 spoons would cost 5 * 3 = $<<5*3=15>>15.
#### 15