Johann maintains a $75,000 insurance policy on his boat. he pays $50 per month in premiums and his deductible is $2,500. if he is involved in an accident and makes a claim of $3,000 on the policy, how much will he have to pay?

The problems states that his deductible is $2500 so he will get $500  ($3000- 2500) from the insurance company.
If this accident happens the first month he has insurance he will also have spent $50 so he will have $450
You did not say how long he has been paying his premiums but I am going to assume it has been a year or 12 months @ $50 or $600.   In that case we do $500-600 = $-100 and he will have to pay $100
I don't care for the question because premiums get paid whether you make a claim or not and should not be considered in how much he will get if he makes a claim.