Answer: You can send or receive a maximum of 21 text messages per month.
Step-by-step explanation:
First, you need to take out the number the phone bill costs (24.99)
29 - 24.99 = 4.01
Then, you need to find out how many 0.19 fit into 4.01.
21 * 0.19 = 3.99. Any more than that and it would go over.