Answer:
$6.25n+$3.50
Step-by-step explanation:
The cost of all the lunch is $6.25 and the cost of delivery of the lunch is $3.50.
The total cost will be cost of lunch + delivery = $6.25+$3.50
= $9.75
Expression that can be used by Mr. Jackson to find the cost of ordering 'n' lunches will be $6.25n+$3.50
Note that the cost of lunch is what will be affected but not the cost of delivery since it is a one time delivery (that is the cost of delivery will not change no mater the amount of lunch ordered "at once".