Answer:
18 yards
Explanation:
Rate = Total amount of sod used / Number of days = 6 yards / 3 days = 2 yards per day
sod used after 9 days by multiplying the rate (2 yards per day) by the number of days (9 days):
Amount of sod used = Rate * Number of days = 2 yards per day * 9 days = 18 yards
after 9 days, the landscaper will use 18 yards of sod