Question

The graph below shows the amount of money charged by two electricity providers per months , depending on the amount of electricity used.

Answer 1

1. Provider B would be cheaper for Catherine.
2. Stephanie uses 30 kWh of electricity per month.

a) To determine which provider is cheaper for Catherine, we need to evaluate the cost for each provider based on Catherine's electricity usage of 360 kWh.

Provider A: Cost_A = x + 15

Provider B: Cost_B = 20 + 25

Let's substitute Catherine's electricity usage (x = 360) into both formulas:

Cost_A = 360 + 15 = 375

Cost_B = 20 + 25 = 45

Therefore, Provider B would be cheaper for Catherine.

b) Since Stephanie pays the same price for electricity from both providers, we can set the two cost formulas equal to each other:

x + 15 = 20 + 25

Now, solve for x (electricity usage):

x = 20 + 25 - 15

x = 30

Stephanie uses 30 kWh of electricity per month.