Theory

➡ Average = Sum of all the Values / Total Number of Values
➡ Sum of all the Values = Average * Total Number of Values

The average (arithmetic mean) of the 15 numbers in a list is 16

Sum of 15 numbers = Average * 15 = 16 * 15 = 240

The average of 12 of the numbers in the list is between 8 and 14

Sum of 12 numbers = Average * 12 = Between 8*12 and 14*12 = Between 96 and 168

The average of the other 3 numbers

Average = Sum/3 = (Sum of 15 numbers - Sum of 12 numbers)/3 = Between \(\frac{240 - 168}{3}\) and \(\frac{240 - 96}{3}\)
= Between \(\frac{72}{3}\) and \(\frac{144}{3}\) = Between 24 and 48

Only 24 and 28 in the answer choices are in this range

So, Answer will be B, C.
Hope it helps!

Watch the following video to Learn the Basics of Statistics

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