Question

What's the sum of an infinite geometric series if the first term is 81 and the common ratio is 2∕3 ?A) 243B) 729C) 567D) 135

Answer 1

A) 243

Explanation:

We have the formula to calculate the sum to infinity of a geometric series is the following:

`s=(a)/(1-r)`

Where a is the first term and r is the common ratio, therefore, we replace and we are left with:

`s=(81)/(1-(2)/(3))=(81)/((1)/(3))=81\cdot3=243`

The sum of an infinite geometric serie is 243