Question

Can the sum of first some teams the arithmetic squence is 8, 14, 20, ... be 356 ? ​

Answer 1

Answer:

Answer: The sum of the arithmetic sequence 8, 14, 20, …, up to 24 terms is Sn = 1848.

Let us find the sum of the given arithmetic sequence.

Explanation:

The sum of the first n terms of an arithmetic sequence when the nth term is NOT known is:

S

n

= n/2 [2a + (n−1)d]

Here, the arithmetic sequence is 8, 14, 20 …,

a = 8

d =

a

2

-

a

1

= 14 - 8 = 6

and given that number of terms is 24, so,

n = 24

S

n

= n/2 [2a + (n−1)d]

S

n

= (24/2) [ 2(8) + (24 - 1)(6) ]

S

n

= 12 [ 16 + 23 × 6 ]

S

n

= 12 [ 154 ]

S

n

= 1848

Thus, the sum of the arithmetic sequence 8, 14, 20, …, up to 24 terms is

S

n

= 1848.