Question

5/9 of 729 find the sum​

Answer 1

Answer:

Given, first term of a GP is a=729

and 7

th

term, a

7

=ar

6

=64

⇒729r

6

=64

⇒r

6

=(

3

2

)

6

⇒r=

3

2

= Common ratio

Therefore, a

1

+a

2

+a

3

+a

4

+a

5

+a

6

+a

7

= Sum of the first seven terms

=

1−r

a(1−r

7

)

=

1−

3

2

729{1−(

3

2

)

7

}

=

729×3

729×3

(729×3−128)

=2059