Question

The arithmetic mean of 3, 4, 6 and \( x \) is 5. Then the value of \( x \) will be :

• A. 5
• B. 2
• C. 7
• D. 3

Hint:

To find an unknown value when the arithmetic mean is given, multiply the mean by the number of observations and subtract the sum of the known values.

Answer 1

The Correct Option is C

The formula for the arithmetic mean is: \[ \text{Arithmetic Mean} = \frac{\text{Sum of all observations}}{\text{Number of observations}} \] Here, we are given that the arithmetic mean of 3, 4, 6, and \( x \) is 5. The number of observations is 4. Therefore: \[ 5 = \frac{3 + 4 + 6 + x}{4} \] Multiplying both sides by 4: \[ 20 = 3 + 4 + 6 + x \] \[ 20 = 13 + x \] Subtract 13 from both sides: \[ x = 7 \] Thus, the value of \( x \) is 7.