Mo has a credit card that gives a 3% discount on every purchase. The annual percentage rate on the card is 12%. He is purchasing an electronic reader for $140. Check all that apply. If Mo uses the credit card and pays the full balance during the billing cycle, the cost of the purchase will be $140.
If Mo pays cash, the cost of the purchase will be $140.
If Mo uses the credit card and pays off the balance at $30 a month for 7 months with no late fees, the cost of the purchase will be $143.34.
If Mo pays cash, the cost of the purchase will be $135.80.
If Mo uses the credit card and pays off the balance at $20 a month for 7 months with no late fees, the cost of the purchase will be $139.89.
If Mo uses the credit card and pays the full balance during the billing cycle, the cost of the purchase will be $135.80.

I want an actual explanation, not just an answer please