She has 100 dollars
Half of 50 is
The pattern :
100, 50, 25, 12.5, 6.25, 3.12, 1.56, 0.78, 0.39, 0.19, 0.9, 0.45. 0.22, 0.11, 0.5, 0.25, 0.12, 0.06, 0.03, 0.01
This is basically as far as it goes I had to round some of the numbers. But since there are 20 terms the number of days is 20
20 days