Every 12 customer at a new york deli gets a free soda every 15th customer gets a free bagel which is the first to get a free bagel and a free soda?

In stepmber, daniel and justin opened a business. during their first three months of business, their average monthly profit was $51. if during their first month, they lost $29, and during their second month, they gained $115, what was their profit or loss for their third plzzz i will give you 299 points