Based on the tip left and its proportion of the total bill, the following answers are true:
A tip of $2.60 was left and this is said to be 20% of the bill including the tax.
The total bill is therefore:
Tip = Total bill x 20%
2.60 = Total bill x 20%
Total bill = 2.60 / 20%
= $13.00
We can see that the tax rate was not needed to compute the total bill.
In conclusion, the tax rate was irrelevant and the total bill was $13.00.
Find out more about taxes and tips in bills at https://brainly.com/question/24976122.