Answer :
Answer:
This is very late but but for helping other people in the future, the answer is 33. I took the test and it's correct. Here is a screenshot:

The relative frequency of selecting a blue marble is 33%
What is relative frequency in probability?
"The relative frequency of an event is the number of times that the event occurs during experimental trials, divided by the total number of trials conducted."
The formula to calculate the relative frequency:
f(A) = n(A)/t
where n(A) = the number of times that the event occurs during experimental trials
t = number of trials
f(A) = relative frequency of an event
What is percent?
"It is a number or ratio that can be expressed as a fraction of 100."
For given example,
A jar contained 18 red marbles, 14 green marbles, and 20 blue marbles.
Let event A: selecting a blue marble
⇒ n(A) = 20
Here, the number of trials (t) = 60
So, the relative frequency of selecting a blue marble would be,
⇒ f(A) = n(A)/t
⇒ f(A) = 20/60
⇒ f(A) = 1/3
The relative frequency to the nearest percent would be,
⇒ f(A) = (1/3 × 100)%
⇒ f(A) = 33.33%
⇒ f(A) ≈ 33%
Therefore, the relative frequency of selecting a blue marble is 33%
Learn more about relative frequency here:
https://brainly.com/question/22885953
#SPJ2