Answer:
c. 60.9%
Step-by-step explanation:
Given:
The probability P that a person responds to an advertisement can be modeled by the function:

where
represents number of days since the advertisement first appeared.
To find the probability that a person has responded after 20 days.
Solution:
In order to find the probability that a person has responded after 20 days, we will plugin
in the formula given.
We have:

Plugging in 





Thus, probability
after 20 days = 0.6094
The probability in percentage can be given =
= 60.9%