Answer:
The D&J Landscape will have to spend less than 9.09 hours in order to be more cost effective.
Explanation:
Greenscape charges $100 for the mulch plus $12 per hr for labor.
D&J landscape charges $23 per hr for the job including the mulch.
Let x be the total number of hours.
Amount charge by Greenscape =

Amount charged by D&J landscape =

Equating both the equations.

Solving for x;


x = 9.09 hours.
Hence, for the D&J landscape company, the minimum hours should be x<9 so as to have a better deal.