Multiple Choice Questions

The average of n observations is 40 If one observation of value 80 is added then the average of all ...........

Quantitative Aptitude (CPO) Average

The average of n observations is 40. If one observation of value 80 is added, then the average of all the observations is 41. What is

the value of n?

This questions was previously asked in

SSC CPO 11th Dec 2019 Shift-2

- Let's denote the sum of the initial n observations as S.

- The average is given as 40, so S/n = 40 which implies S = 40n.

- When an observation of 80 is added, the total sum becomes S + 80.

- The new average is 41, hence (S + 80) / (n + 1) = 41.

- Substituting S = 40n into the equation gives: (40n + 80) / (n + 1) = 41.

- Solving for n, this equation simplifies to n = 39.

Option 2: 39 is the correct answer.

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