Answer:
4 months
Step-by-step explanation:
Club A
registration fee: $0
monthly fee: $105
After every month, the total cost increases by $105.
month 0: $0
month 1: $105
month 2: $210
month 3: $315
month 4: $420
month 5: $525
month 6: $630
Club B
registration fee: $375
monthly fee: $80
Notice how Club B's total reaches Club A's total after 2 months.
month 0: $375
month 1: $455
month 2: $535
month 3: $615
month 4: $695
