Answer:
The sum of the first 41 terms is 6232
Step-by-step explanation:
The sequence is an arithmetic progression with:
[tex]a = 12[/tex] -- first term
[tex]d = 7[/tex] --- common difference (this is calculated by 19 - 12 or 26 -19)
Required
The sum of the first 41 terms
This is calculated as:
[tex]S_n = \frac{n}{2}(2a + (n-1)*d)[/tex]
In this case: [tex]n = 41[/tex]
So:
[tex]S_{41} = \frac{41}{2}(2*12 + (41-1)*7)[/tex]
[tex]S_{41}= \frac{41}{2}*304[/tex]
[tex]S_{41} = 6232[/tex]
