Multiple choice

The mean of $4$ observations is $16$, including one new observation, the mean is $20$. Find the newly included observation.

  1. 100

  2. 60

  3. 70

  4. 36
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D Correct answer
Explanation

Sum of 4 observations = 4 * 16 = 64. Sum of 5 observations = 5 * 20 = 100. The new observation = 100 - 64 = 36.

AI explanation

The initial total sum for the 4 observations is 4 multiplied by 16, which equals 64. The new total sum for the 5 observations is 5 multiplied by 20, giving 100. The value of the newly included observation is the difference between the new sum and the initial sum, which is 100 minus 64, resulting in 36.

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