Answer: (total amount paid - $40) / 0.05
Step-by-step explanation:
Given the following :
Monthly fee = $40
Additional fee = $0.05 per minute on phone
Given the the amount paid for the month is available, number of minutes he was on phone can be determined thus :
Total amount to be paid = monthly fee + additional fee
Additional fee = $0.05 × n
Where n = number of minutes on phone
Hence,
Total amount paid = $40 + $0.05n
If the amount paid is known, the number of minutes on phone can be calculated thus;
(Total amount paid - monthly fee) = $0.05n
n = (Total amount paid - monthly fee) / fee per minute on phone
(total amount paid - $40) / 0.05
