Answer:
I think buying a new mower will be a much more financial sound decision because it can last 3 years, however, if you hire landscapers it will cost significantly much more money than buying a new mower.
Explanation:
Reason for this is that: 
$18×2000 hours= $36,000 each year 
For three years: $36,000×3=$108,000 
which is more than $8,000 
Hence, buying a new mower would be the better solution.