Question

Find S for the given geometric series. Round answers to the nearest hundredth, if necessary.

a1=0.2, a5=259.2, r=6

a) 311
b)51
c)222.2
d)624.96

Answer 1

A

Explanation:

Sum of the first n terms of a geometric series is:

S = a₁ (1 - r^n) / (1 - r)

Here, a₁ = 0.2, r = 6, and n = 5.

S = 0.2 (1 - 6^5) / (1 - 6)

S = 311

Answer 2

Option A

Explanation:

For the given geometric series

a₁ = 0.2

a₅ = 259.2

r = 6

Then we have to find the sum of initial 5 terms of this series

`S_(n) =(a_1(r^4-1))/((r-1))=(0.2(6^3-1))/((6-1))`

`=(0.2(7776-1))/(5)`

`(0.2* 7775)/(5)`

= 311

Option A is the answer.