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Question

The arithmetic mean of 100 observations is 50. If 10 is added to each observation then what will be the new arithmetic mean ?

This question was previously asked in
CDS 1 2026 Maths Question Paper (12-Apr-2026)
The correct answer is
60

Arithmetic Mean Property for Adding Constants

We are given that the arithmetic mean of 100 observations is 50.

A key property of the arithmetic mean is that if a constant value is added to every observation in a dataset, the mean of the dataset increases by that same constant value.

In this case:

  • Original Mean (\(\bar{x}\)) = 50
  • Constant Added to Each Observation = 10

Calculating the New Arithmetic Mean

Using the property mentioned above, the new arithmetic mean can be calculated directly:

\(\text{New Mean} = \text{Original Mean} + \text{Constant Added}\)

\(\text{New Mean} = 50 + 10\)

\(\text{New Mean} = 60\)

Therefore, the new arithmetic mean will be 60.

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