Average age of 8 men is increased by 2,years when two of them whose ages are 21, years and 23, years

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4.Average

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The average age of $8$ men is increased by $2\,years$ when two of them whose ages are $21\, years$ and $23\, years$ are replaced by two new men. The average age of the two new men is

A

$22$

B

$24$

C

$28$

D

$30$

Solution

Let average age of $8$ men be $x$.

Let the average age of two men joining be $y$. On joining $2$ persons by replacing two persons of ages $21$ and $23\, years$

New average $=\frac{8 \times x-21-23+2 y}{8}=x+2$

$8 x-44+2 y=8 x+16$

$2 y=44+16=60$

$y=30$ years

Standard 13

Quantitative Aptitude

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