Answer:
12
Explanation:
In this question, it means that the price of 13.80 is inclusive of the tip. This means that the price is 115% of the normal price. Then we must ask ourselves, if the price of 13.80 is 115%, what is 100%?
That is,
13.80 =115%
? = 100%
We work it out as follows:
(100/115)* 13.80
= 12