Joaquin can send between at most 250 text messages per month. Since he has already sent 141, we must have
.. 141 +t ≤ 250
The solution to this model of the situation can be found by subtracting 141.
.. t ≤ 109
We graph the lower limit as zero because we know Joaquin cannot send a negative number of text messages.
Interpretation:
Joaquin can send between 0 and 109 additional text messages this month.