Final answer:
To calculate the 20X7 telephone expense, add up the amounts paid for each bill during that year.
Step-by-step explanation:
To calculate the 20X7 telephone expense, we need to add up the amounts paid for each bill during that year.
The amounts paid in Nov 20X6 - Jan 20X7, Feb 20X7 - Apr 20X7, May 20X7 - Jul 20X7, and Aug 20X7 - Oct 20X7 are all valid for the 20X7 expense.
Therefore, the 20X7 telephone expense is 450 + 480 + 410 + 460 = $1,800.