JEE Mains · Maths · STD 11 - 13. statistics
The mean age of \(25\) teachers in a school is \(40\) years. A teacher retires at the age of \(60\) years and a new teacher is appointed in his place. If the mean age of the teachers in this school now is \(39\) years, then the age (in years) of the newly appointed teacher is..........
- A \(40\)
- B \(35\)
- C \(48\)
- D \(56\)
Answer & Solution
Correct Answer
(B) \(35\)
Step-by-step Solution
Detailed explanation
\(\frac{\sum x _{ i }}{25}=40 \& \frac{\sum x _{ i }-60+ N }{25}=39\) Let age of newly appointed teacher is \(N\) \(\Rightarrow 1000-60+ N =975\) \(\Rightarrow N =35\) years
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