Final answer:
Payment plan A with a $30 monthly installment will pay off the phone in 5 months.
Step-by-step explanation:
To determine which payment plan will pay off the phone in the fastest time, we need to calculate the total cost of each plan and compare them.
Plan A: $30 monthly installment
Total cost = $150 / $30 = 5 months
Plan B: $15 monthly installment
Total cost = $150 / $15 = 10 months
Plan C: $10 monthly installment
Total cost = $150 / $10 = 15 months
Plan D: $25 monthly installment
Total cost = $150 / $25 = 6 months
Based on these calculations, Payment plan A will pay off the phone in the fastest time, as it takes only 5 months to pay off the $150.