SSC CGL 23 Aug 2021 Shift 2 Paper

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Question : 24 of 100

Marks: +1, -0

The average age of 17 persons is

39 {yr}

. If the average age of the first 9 persons is

35 {yr}

and the average age of the last 9 persons is

44 {yr}

, what is the age of the 9 th person?

$48 {yr}$
$45 {yr}$
$41 {yr}$
$36 {yr}$

Solution:

Given, average age of 17 persons is

39 {yr}

.
Total age of 17 persons

\table =39 × 17=663 {yr} ]

{[ ∵ \;\text " Average "\;=\;{\;\text " Sum of terms "\;}/{\;\text " Total terms "\;}]} .

Total age of 9 person

=35 × 9=315 {yr}

Total age of remaining 9 persons

=44 × 9=396 {yr}

∴

Age of 9 th persons

\;\; =(315+396)-663 {yr}

\;\; =711-663=48 {yr}

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