Multiple choice

If the average of x, y, z and w is a, then find the average of x, y and a.

  1. 5a/3

  2. 5a

  3. [5a - (z + w)]/3

  4. Insufficient data

  5. [5a + z + w]/3
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The average of x, y, z and w is a.

So, a = (x + y + z + w)/4    --------------(1)

Now, average of x, y and a = (x + y + a)/3

On putting the value of (x + y) from equation (1) 

= (4a - z - w + a)/3

= [5a - (z + w)]/3

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