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  • The mean of five numbers is 30. If one number is excluded, their mean becomes 28. The excluded number is : (A) 28 (B) 30 (C) 35 (D) 38

The mean of five numbers is 30. If one number is excluded, their mean becomes 28. The excluded number is :

\\(A) 28\\ (B) 30\\ (C) 35\\ (D) 38

Answers (1)

Answer : D

Let the numbers be

a+b+c+d+e

\Rightarrow Mean =\frac{a+b+c+d+e}{5}=30

\Rightarrow a+b+c+d+e=30 \times 5=150\; \; \; \; \; \; \; \; \; \; \; \; ....(i)

Let the excluded number be a

New mean =28

\Rightarrow \frac{b+c+d+e}{4}=28

\Rightarrow b+c+d+e=28\times 4=112

Putting the value of  b+c+d+e in equation (i)

a+112=150

\Rightarrow a=150-112

\Rightarrow a=38\; \; \; \; \; \; \; \; \; \; \rightarrow\text{excluded number}

Therefore option (D) is correct.

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infoexpert23

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