The answer to your question is 0.1
The compound interest formula is : 
where, A= Future value including the interest,
P= Principle amount, r= rate of interest in decimal form,
t= number of years and n= number of compounding in a year
Here, in this problem P= $ 51,123.21 , t= 20 years and 2 months
So, t= 20 + (2/12) years
t= 20 + 0.17 = 20.17 years
As the amount is compounded daily, so n= (12×30)= 360 [Using the traditional Banker’s rule of 30 days per month]
Thus, 
When the interest rate is given, then we can use this equation for finding the future value.
For part a it’s sal will leave a $20 tip for part b sals food is $78.22 including tax and tip
Answer:
(6, 3)
Step-by-step explanation:

How to Calculate Midpoint?
The x-coordinate of the midpoint M of the segment
is the arithmetic mean of the x-coordinates of the endpoints of the segment
. Similarly, the y-coordinate of the midpoint M of the segment
is the arithmetic mean of the y-coordinates of the endpoints of the segment
.