Given that,
Michael is leaving a 15% tip for his waitress.
To find,
What percent of the original price will he pay.
Solution,
Let the original price was 100%.
When he leaves a 15% tip for the waitress, he is really paying 100%+15%=115% of the original price.
[tex]115\%=\dfrac{115}{100}\\\\=1.15[/tex]
or
[tex]\dfrac{115}{100}=\dfrac{23}{20}[/tex]
So, this is the required solution.