Given:
The cost per message is $0.25.
Jules spent $8 already, and she has a total of $15 this month.
Let x be the number of massages.
The number of messages sent in $8 is,
The inequality for total massages can be sent in $15 is written as,
For $15, Jules can send a maximum of 60 massages.
But as she already spent $8 now, her balance now is 15 - 8= $7.
So, in the remaining balance, she can send,
Answer: Jules can send a maximum of 60 massages for $15.
And after spending $8, she can send a maximum of 28 massages.