Answer:
The Inequality representing the number of messages send or receive is

After 34 messages the unlimited plan would be cheaper than paying for each messages.
Explanation:
Given:
Cost of each message = $0.15
Cost of Unlimited plan = $5.00
We need to find number of messages she can send receive till Unlimited plan will be cheaper than paying for each message.
Solution:
Let the number of messages be 'x'.
So we can say that;
Cost of each message multiplied by number of messages should be greater than Cost of Unlimited plan.
framing in equation form we get;

The Inequality representing the number of messages send or receive is

On Solving the inequality we get;
Dividing both side by 0.15 we get;

Hence After 34 messages the unlimited plan would be cheaper than paying for each messages.