Final answer:
Glenn can pay for his cell phone for 27 months before incurring fees.
Step-by-step explanation:
To determine the number of months Glenn can pay for his cell phone before incurring fees, we can set up an inequality. Let's assume that he can pay for x months before incurring fees. Glenn must keep a minimum of $150 in his account, so the amount of money available for paying the cell phone bill each month would be $1,250 - $150 = $1,100. Since the cell phone costs him $35 per month, the inequality becomes: $1,100 - $35x >= $150.
To solve this inequality, we can subtract $150 from both sides to isolate the variable: $1,100 - $150 - $35x >= $150 - $150, which simplifies to $950 - $35x >= $0. Next, we can subtract $950 from both sides: $950 - $950 - $35x >= $0 - $950, which simplifies to $0 - $35x >= -$950.
Finally, we divide both sides of the inequality by -35 (remember, dividing or multiplying by a negative number switches the inequality symbol): (-35x) / -35 <= -$950 / -35, which simplifies to x <= 27.14. Since Glenn cannot have a fraction of a month, the number of months he can pay for his cell phone before incurring fees is 27.