Answer:
52.40
Step-by-step explanation:
Discussion
Suppose the meal starts out as x.
She pays 5% of x as a sales tax
So that brings the total up to 100% + 5% = 105%
Before paying, she pays 20% on x as her tip. The tax does not touch the tip.
So that brings the total up to 100% + 5% + 20% = 125% of this is based on x, the cost of the meal.
So 125% of x = 65.50                          change the % to a fraction
125/100 * x = 65.50                             Multiply both sides by 100/125  
125/100 * 100/125x = 100/125 * 65.50
x = 100/125 * 65.50                             Multiply by 100 
x = 6550 / 125                                     Divide by 125
Check 
Tax = 5% * 52.40 = 5/100 * 52.40 = 2.62 
Tip = 20%*52.40 = 20/100 * 52.40=10.48
Meal =                                               52.40
Total                                                  65.50  Just as it should