For this case we have:
Let x be the number of weeks you should work in the store. We have:

That is,
represents the profit obtained according to the number of weeks worked.
65, represents the gain obtained in one night, in the store.
Cole's earnings must be greater than or equal to the cost of the trip and stay of the singing competition, so he can cover it.
Clearing x:



Thus, the minimum number of weeks that Cole must work to cover the costs of the competition is 6.
Answer:
The minimum number of weeks is 6.
