Respuesta :
Answer:
[tex]S_n=978\ minutes[/tex]
Step-by-step explanation:
Arithmetic sequences have the following form
[tex]a_n=a_1+d(n-1)[/tex]
Where
[tex]a_1[/tex] is the first term of the series
d is the common difference between consecutive terms.
[tex]a_n[/tex] is the nth term.
The formula to find the sum Sn of the first n terms of an arithmetic series is:
[tex]S_n=\frac{a_1+a_n}{2}*n[/tex]
In this case [tex]n=12[/tex], [tex]d=3[/tex], [tex]a_1=65[/tex]
[tex]a_{12}=65+3(12-1)[/tex]
[tex]a_{12}=98[/tex]
Then:
[tex]S_n=\frac{65+98}{2}*12[/tex]
[tex]S_n=978\ minutes[/tex]
You can also find the sum through the following series
[tex]S_n=\sum_{n=1}^{n=12}a_1+d(n-1)[/tex]
[tex]S_n=\sum_{n=1}^{n=12}65+3(n-1)[/tex]
[tex]S_n=\sum_{n=1}^{n=12}65+3(n-1)\\\\S_n=978[/tex]
The total length of all 12 movies using the concept of an arithmetic progression is 978 min
What is an arithmetic progression?
It is a series of numbers where the difference between two consecutive terms is equal.
Formula to find the sum of an arithmetic progression is
[tex]Sn = \frac{n}{2} (2a + (n-1)d)[/tex]
Where Sn = sum of arithmetic series
a = first term of the series
n = total terms of the series
d = common difference
It is given that
a = 65
n =12
d =3
[tex]Sn = \frac{12}{2} (2*65 + (12-1)*3)[/tex]
[tex]Sn = 978min[/tex]
Therefore, the total length of all 12 movies is 978 min.
To get more about arithmetic progression visit:
https://brainly.com/question/18828482