Answer:
$1.02 or 102 cents
Step-by-step explanation:
According to given information
Total consumption Time = 120 Hours
Cost Saving per hour = Cost per hour x Saving in kilowatts per hour
Cost Saving per hour = Cost per hour x ((100 watts - 15 watts) / 1000)
Cost Saving per hour = $0.1 x (100-15)/1000 = $0.0085 kwh
Total Cost Saving = 120 x 0.0085 kwh = $1.02 or 102 cents