Question

What is the sum of a 6–term geometric series if the first term is 24 and the last term is 1,417,176?

Answer 1

\[S = a \times {1 - r^n \over 1 - r}\]

Answer 2

We already have the value of \(a\); just to find \(r\).

Answer 3

There are 5 terms in between term 1 and 6.

Answer 4

\[ \color{Black}{\Rightarrow {{1,417,176 \over 24} \over 5} }\]

Answer 5

That is \(r\). Can you do the rest?

Answer 6

what is a?

Answer 7

See you are given last term and first term:

a = 24 and \(a_n\) = 1417176

So:

\[\large a_n = a \cdot r^{n-1}\]

here n = 6 given a = 24 and r = ??? and \(a_n = 1417176\)

Can you find r from it??

Answer 8

i got r = 11,809.8

Answer 9

Wait...

Answer 10

\[(24) \cdot r^{6-1} = 1417176\]

Can yo tell me what is 6 - 1 = ??

Answer 11

5

Answer 12

So what you get in power of r now ??

Answer 13

\[24 \cdot r^5 = 1417176\]

Now divide by 24 both the sides..

And tell me what do you get??

Answer 14

@emkaye16 I am expecting your reply here..

Simply divide 24 with 24 in LHS..

And divide 1417176 by 24 and tell me what do you get..

Answer 15

Can you tell me what is :

1417176/24 = ??

You can use calculator no doubt..

Answer 16

thankyou sorry i did not reply