An electric bill varies directly as the amount of electricit

An electric bill varies directly as the amount of electricity used. The bill for 1400 kilowatts of electricity is exist98. What is the bill for 2200 kilowatts of electricity? You are choosing between two long-distance telephone plans. Plan A has a monthly fee of exist20 with a charge ofexist0.05 per minute for all long-distance calls. Plan B has a monthly fee of exist5with a charge of exist0.10 per minute for all long- distance calls. Express the monthly cost for plan A, f, as a function of the number of minutes of long-distance calls in a month, x. Express the monthly cost for plan B, g, as a function of the number of minutes of long-distance calls in a month, x. For how many minutes of long-distance calls will the costs for the two plans be the same?

Solution

(4) we have Electric bill varies directly with electricity used

Bill = k*Units

98=k*1400

Bill = k*2200

Bill = (98/1400)*2200 = $154

So bill is $154

Q5 (a) Function will be = 20+0.05x

(b) Function will be = 5+0.10x

(c) 20+0.05x=5+0.10x

15 = 0.05x-0.1x

x = 300 minutes