Final answer:
The school office uses a total of 5r + 15 reams of paper in five days.
Step-by-step explanation:
To find the total amount of paper the school office uses in five days, we need to multiply the number of reams used per day by the number of days. The office uses r reams of white paper and 3 reams of blue paper per day.
So, the expression for the total amount of paper used in five days is:
(r reams/day + 3 reams/day) * 5 days
To simplify the expression, we can distribute the multiplication to both terms inside the parentheses:
(r * 5 reams/day) + (3 * 5 reams/day)
Which simplifies to:
5r reams + 15 reams
Therefore, the school office uses a total of 5r + 15 reams of paper in five days.