Final answer:
To find the most number of messages you can afford to send, subtract the fixed monthly cost from your budget and then divide the remaining amount by the cost per text message.
Step-by-step explanation:
To find the most number of messages you can afford to send, you need to subtract the fixed monthly cost from your budget and then divide the remaining amount by the cost per text message. In this case, the fixed monthly cost is $64.50 and the cost per text message is $0.05. So the calculation would be:
Number of messages = (Budget - Fixed cost) / Cost per message
Number of messages = ($120 - $64.50) / $0.05
Number of messages = $55.50 / $0.05
Number of messages = 1110
Therefore, the most number of messages you can afford to send is 1110.