Answer: $13.75
Explanation:
Since Mrs. Chin paid a 20 percent tip on the bill for lunch and the tip amount was $2.75, then the bill for lunch before the tip was added to it will be calculated thus:
Let the bill for lunch be represented by x. Therefore,
20% of x = $2.75
20/100 × x = $2.75
0.2 × x = $2.75
0.2x = $2.75
x = $2.75/0.2
x = $13.75
Therefore, the bill is $13.75 before the too was added.