Chart for question attached
Answer:
Joshua
Step-by-step explanation:
By cost-effective here, we mean the contractor that does the job best at the shortest time and lowest money cost. To get this, we calculate total cost for each contractor and then consider time for completion of the job:
Joshua charges $25 per hour for 5 hrs
Carmen charges $20 per hour for 7 hrs
Dante charges $30 per hour for 6 hrs
Alicia charges $20 per hour for 8 hrs
Joshua's cost= $25×5=$125 in 5 hours
Carmen's cost = $20×7= $140 in 7 hours
Dante's cost= $30×6=$180 in 6 hours
Alicia's cost= $20×8= $160 in 8 hours
From the above we can see that Joshua is the most cost-effective contractor given that he completes the job in less time and with less money.