Answer:
100 days
Step-by-step explanation:
Are you trying to determine how many days it will be until the charges of the two different companies are equal?
If so, here's the equation: $20 + ($1.10/day)d = ($1.30/day)d
This simplifies to $20 = $(0.20)d, which yields 100 days.
After 100 days, the two companies will have taken in the same amount.