The average of X, Y and Z is 2X. If the average of Y and Z is 20, then what is the value of X?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 8.
We know that,
Average = Sum of observations/Number of observations
Given that,
Average of X, Y and Z = 2X
⇒ X + Y + Z = 6X
⇒ Y + Z = 5X ....(i)
Also, the average of Y and Z = 20
⇒ Y + Z = 40 ...(ii)
Now, from equations (i) and (ii),
⇒ 5X = 40
⇒ X = 40/5
⇒ X = 8.
Hence, the value of X is 8