Answer:
A.) value of the tax
B.)The total bill corresponds to $ 17.50
Explanation:
To calculate the value of the meal, the data we do not need to know is the value of the tax because it is included in the total cost of the meal.
We know that the tip corresponds to 20% of the total 100% that we have to find out
To find out we apply a simple rule of three

The total bill corresponds to $ 17.50