Rachel, Xandra and Ivory each sold an equal number of puffs. Rachel collected a total of $52.60 from selling 9 matcha puffs and some chocolate puffs. Xandra collected a total of $66.40 from selling 15 matcha puffs and some chocolate puffs. How much did Ivory collect if she sold only chocolate puffs?
Xandra collected more money than Rachel from the sale of the puffs but the number of puffs sold by each girl was the same. This shows that each matcha muffin is higher priced than each chocolate muffin. 

Amount that Xandra collected more than Rachel
= 66.40 - 52.60
= $13.80

Number of more matcha puffs that Xandra sold
= 15 - 9
= 6

Extra amount collected from the sale of each matcha muffin
= 13.80 ÷ 6
= $2.30

Total extra amount collected from the sale of 9 matcha puffs
= 9 x 2.30
= $20.70

If Rachel sold only chocolate puffs, she would collect $20.70 less than her original amount.

Amount that Ivory collected if she sold only chocolate puffs
= 52.60 - 20.70
= $31.90

Answer(s): $31.90