History: Find the number of terms, n, of the arithmetic series given a = 21, an = 39, and Sn = 210. A.7 B. 8 C. 9 D.5

Find the number of terms, n, of the arithmetic

Ответ:

organdonor626

21.01.2022

History

The number of terms n is 7.

Explanation:

Given that:

First term a=21

nth term $a_{n}$ =39

Sum up to n terms $S_{n}$ =210

To Find:

The number of terms n in the arithmetic progression.

Formula to be used:

Sum up to n terms Sn is given by the expression

$S_{n} =\frac{n}{2} (a+a_{n} )$

Solution:

$S_{n} =\frac{n}{2} (a+a_{n} )\\\\210=\frac{n}{2}(21+39)\\\\210=\frac{n}{2}(60)=30n\\\\n=210/30=7$

Number of terms n in the given series is n=7

0,0(0 оценок)

Ответ:

nellydeb7736

25.11.2020

History

The massacre of unarmed civilians damaged support for the war is why the tet offensive considered a turning point in the vietnam war but a and d are also true point is that that wasn't reason why it was turning point of war

0,0(0 оценок)

Find the number of terms, n, of the arithmetic series given a = 21, an = 39, and Sn = 210.
A.7
B. 8
C. 9
D.5

Ответ:

Ответ:

Ask your question to the AI advisor

More tips

Answers on questions: History

Ask an AI advisor a question