Question

Find the sum of first forty positive integers divisible by 6.

Answer 1

HEY THERE!!

Question;-

Find the sum of first forty positive integers divisible by 6.

Method of Solution;-

Let to be first term'a' and Common difference' d' as last last term 'l'.

The positive integers that are divisible by 6 which are given in the form of Arithmetic Sequence or Progression;-

6,12,18,24.....

Here,

First term= 6

Common difference=6

Number of terms= 40

According to the formula of Summation of Arithmetic Progression (AP).

$Sn = \frac{n}{2} [2(a) + (n - 1)d \\ \\ Sn = \frac{40}{2} [ 2(6) + (40- 1)6 \\ \\ \\ \\ Sn = \frac{ \cancel40}{ \cancel2} [ 2(6) + (40- 1)6 \\ \\ \\ Sn = 20 [2(6) + (40- 1)6 \\ \\ \\ \\ \\ Sn = 20 ( 12 + 39×6 \\ \\ \\ \\ \\ \\ Sn = 20(12 + 234) \\ \\ \\ \\ \\Sn = 20 \times 246 \\ Sn = 4920$

Answer 2

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