Question

A certain list consists of 21 different numbers. If n is in the list and n is 4 times the average (arithmetic mean) of the other 20 numbers in the list, then n is what fraction of the sum of the 21 numbers in the list?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

Let average of 20 numbers = a;

Given, n=4a;

Sum of 21 numbers =20\(\timesa\)+4a = 24a;

$\frac{n}{sum}=\frac{4a}{24a}=\frac{1}{6}$