Question

What is the average of the first 15 multiples of 13?​

Answer 1

Answer:

13,26,39,52,65,78, 91,104,117,130,143,156,169,182,195.

Answer 2

Concept:

Average can be calculated as the ratio of the sum of observations to the total number of observations.

Given:

The first 15 multiples of 13.

Find:

The average of the first 15 multiples of 13.

Solution:

The sum of the 15 multiples of 13 is calculated using the arithmetic progression as the 15 multiples of 13 are in arithmetic progression, where a is 13, d is 13 and n is 15.

Substiuting the values,

S = (n/2)[2a +( n - 1) d]

S = (15/2)[2(13) +(15 - 1) 13] = (15/2)[26 +182]

S = 1560

Number of observations is 15, as there are 15 multiples,

Average = S/n = 1560/15

Average = 104

Hence, the average of the first 15 multiples of 13 is 104.

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