Of the people stand in a line waiting for service, 20% have waited for

Drawing a timeline and filling in the info provided from the question stem in purple and what I have sold for in green:

We are told that 20% of the the people have waited for longer than 5min, therefore 80% have waited for less.
We are also told that 8% waited for longer than 8min, so therefore 12% have waited from between 5min and 8min.

­------------ 5min------------ 8min--------->
                 |_____(12%)__|__(8%)__|
|__(80%)__|_________(20%)_______|
                                         
To solve the question we want to know how many 12% of the queue is.


(1) 20 people waited for no more than 5 minutes.

We know that 80% of people waited less than 5 minutes and that this amounts to 20 people. This will be sufficient to solve for 12% of the people in the queue.

Let the amount of people standing in line be \(x\): \(\frac{4}{5}x = 20\)

\(x = 25\)

And 12% of 25 is 3.

SUFFICIENT


(2) 2 people have waited for more than 8 minutes.

With this we know that 2 people are 8%, and as 12% is just 50% more, then there 3 people who have waited for more than 5 minutes and no more than 8 minutes

SUFFICIENT



​​​​​​​ANSWER D

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