A graph showing the monthly cost of an electricity bill for October using the energy companyName: Date:

**Synergy**is shown above. The monthly cost of an electricity bill using a different energy company

**ADF Energy**is calculated as follows:

**Total Cost (£) = Fixed Monthly Charge of £5.00 + £0.20 x Units of energy used**

1) Draw a graph showing the total monthly cost using the energy company

**ADF Energy**

2) Write down the Fixed Monthly Charge of

**Synergy**in pounds

3) Calculate the cost per unit of energy used for

**Synergy**, in pounds, up to 200 units of energy

4) What would be the total monthly cost with

**Synergy**if 100 units were used?

5) If the total monthly cost with

**ADF Energy**is £25.00, how many units of energy were used?

6) Compare the total monthly cost of the two energy companies for different energy usages.

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3) The cost per unit of energy for

4) The total monthly cost of using 100 units with

5) 100 units of energy were used.

6)

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2) The Fixed Charge of**Synergy**= £21.00

3) The cost per unit of energy for

**Synergy**= £0.10 , if up to 200 units of energy are used.

4) The total monthly cost of using 100 units with

**Synergy**= £31.00

5) 100 units of energy were used.

6)

**ADF Energy**is cheaper when less than 160 or more than 220 units of energy are used. They cost the same when exactly 160 or 220 units of energy are used.

**Synergy**is cheaper in between 160 and 220 units of energy.

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