Question

2. Find the average of 9,11, 13, 15 and 17.
(a) 13
(b) 15
(c) 12
(d) 14
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Answer 1

(a) 13 is the average of 9 , 11 , 13 , 15 and 17.

Answer 2

Given :

• Numbers :- 9,11, 13, 15 and 17

To find :

• Average of given numbers.

Formula used :

$\large \sf \: a = \dfrac{s}{n}$

Where :-

• a = average
• s = sum of given observations
• n = Number of observations

Solution :

Observations :- 9,11, 13, 15 and 17

Number of observations = 5

$\implies\large \sf \: a = \dfrac{s}{n}$

$\large \sf \implies \: a = \dfrac{9 + 11 + 13 + 15 + 17}{5}$

$\large \sf \implies \: a = \dfrac{65 }{5}$

$\large \sf \implies \: a = \dfrac{ \cancel{65 } \: \: 13}{ \cancel5 \: \: 1}$

$\large \sf \implies \: a = 13$

Answer :

The average of 9,11, 13, 15 and 17 = 13

Therefore, option (a) is correct.

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Learn more :-

1. a×n = s

2. n = s/a

Where :-

• a = average
• s = sum of given observations
• n = Number of observations