How many end office codes were there pre-1984, when each end office was named by its three-digit area code and the first three digits of the local number? area codes started with a digit in the range 2–9, had a 0 or 1 as the second digit, and ended with any digit. the first two digits of a local number were always in the range 2–9. the third digit could be any digit.

area code can be 602 but not 134 as first digit should be 2-9 and the second digit should be 0 or 1. So the number of possible area codes were 8 X 2 X 10 = 160.

Similarly for first 3 digits - we have 8 X 8 X 10 = 640 possibilities.

Explanation:

from the information given in the question that area code should start with digit  range of digit 2 to 9 and 0 and 1 may be as second digit, while third digit can be any digit. Therefore we have

Take an example -  area code can be 602 but not 134 as first digit should be 2-9 and the second digit should be 0 or 1. So the number of possible area codes were 8 X 2 X 10 = 160.

Similarly for first 3 digits - we have 8 X 8 X 10 = 640 possibilities.

yes we can change both the color of the value of a cell as well as background color of a cell at the same time .

as we know that excel sheet consists of columns and rows.

and intersection of column and row is called cell.

we can change color of the cell and background of the cell at the same time.

hence the statement that

can a person change color of the cell and background of the cell at the same time is true.