The problem describes a piecewise function for electricity charges. For usage up to 1200 kWh, the charge is $7.10 plus 6.747$ cents per kWh. For usage exceeding 1200 kWh, the charge is $88.064$ plus $4.788$ cents per kWh above 1200 kWh. The problem asks to calculate the monthly charge for 910 kWh.

1. Problem Description

The problem describes a piecewise function for electricity charges. For usage up to 1200 kWh, the charge is $7.10 plus 6.747$ cents per kWh. For usage exceeding 1200 kWh, the charge is $88.064$ plus $4.788$ cents per kWh above 1200 kWh. The problem asks to calculate the monthly charge for 910 kWh.

2. Solution Steps

Since the usage is 910 kWh, which is less than or equal to 1200 kWh, we use the first part of the piecewise function.

First, convert the cents to dollars: $6.747$ cents = $0.06747$ dollars.

The formula for the charge when $x \le 1200$ is:

$f(x) = 7.10 + 0.06747x$

Plug in $x = 910$:

$f(910) = 7.10 + 0.06747 \times 910$

$f(910) = 7.10 + 61.3977$

$f(910) = 68.4977$

Round to two decimal places:

$f(910) \approx 68.50$

3. Final Answer

$68.50$