Hello there! The amount of the tip is $2.52. We can find the cost of the bill by taking the numbers we already know:
We know that Mark’s food costs $12 and a sales tax of $0.60 in addition to the bill. That gives us a total of $12.60 for Mark’s bill.
Now that we have the bill, we can use what we have. Because Mark plans to pay a 20% tip on what the bill is (including sales tax), we can say that 100% - 20% = 80%.
To find the amount of the tip, we need to find 20% of $12.60. We can start by finding 10%:
$12.60 divided by 10 gives us $1.26.
Now we can multiply 10% by 2 to get 20%:
$1.26 • 2 = $2.52
Hence, the total bill adds up to $2.52. If you need any extra help, let me know and I will gladly assist you.