**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%**

product means multiply, sum means add

so add 5+k = (5+k)

now multiply that by 6 to get

**6(5+k)**

**Answer: 2(4)+3(4)^3≠5(4)4 **

**Step-by-step explanation: i just answered it and I was correct. **

**Answer:**

415

**Step-by-step explanation:**

You can try to use the internet for the answer to some of those questions.