Answer:
Step-by-step explanation:
Amplitude is twice the coefficent of the sine function. In this case, 
Period is
divided by the coefficent of x, in this case, 
Phase shift, is how much you sum or subctract from x inside the sine, in this case
.
Midline you get by hiding the sine and reading what's left, in this case, -4.
She would've put 11 dimes in each pile. 55/5=11
If they left 15% the tip should be
$11.40, making the total fee $87.40
Hope this helped! I decided to write it out for you so it would be easier to explain.