Final answer:
Carly's total phone bill this month is $52, which includes her $28 monthly plan cost and $24 for using 2 gigabytes of data.
Step-by-step explanation:
Carly's total phone bill for this month can be calculated by adding the monthly plan cost to the cost for 2 gigabytes of data. Since her plan costs $28 per month and each gigabyte of data adds an additional $12, we need to multiply the cost per gigabyte by the number of gigabytes used and then add this to the monthly plan cost.
For 2 gigabytes, the calculation would be: $12 * 2 = $24 for data. Adding the monthly plan cost: $24 (for data) + $28 (monthly plan cost) equals $52 for the total phone bill.