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**A student was asked to find the arithmetic mean of the numbers 3, 11, 7, 9, 15, 13, 8, 19, 17, 21, 14 and x. He found mean to be 12. What should be the number in place of x?
**

A. 3 B. 7 C. 17 D. 31
**Answer: Option B**

## Show Answer

Solution(By Apex Team)

$\begin{aligned}&\text{ Clearly, we have }\\ &\Rightarrow\frac{3+11+7+9+15+13+8+8+19+17+21+14+x}{12} =12\\ &\Rightarrow137+x=144\\ &\Rightarrow x=144-137\\ &\Rightarrow x=7\end{aligned}$

## Related Questions On Average

### Ajit has a certain average for 9 innings. In the tenth innings, he scores 100 runs thereby increasing his average19 people went to a hotel for combine dinner party 13 by 8 runs. His new average is:

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### If the arithmetic mean of 0, 5, 4, 3 is a, that of -1, 0, 1, 5, 4, 3 is b and that of 5, 4, 3 is c, then the relation between a, b, and c is.

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