Average of 6 numbers is 8. 7^{th} number so that average becomes 10 ?

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4.Average

easy

The average of $6$ numbers is $8.$ What is the $7^{th}$ number so that average becomes $10 ?$

A

$22$

B

$18$

C

$21$

D

$20$

Solution

Let the $7^{th}$ number be $x$.

According to the question

$6 \times 8+x=7 \times 10 \Rightarrow x=70-48=22$

Standard 13

Quantitative Aptitude

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