Question

The sum of the first 6 terms of a geometric series is

Answer 1

Answer:

4

Step-by-step explanation:

The sum to n terms of a geometric sequence is

$S_{n}$ = $\frac{a(r^n-1)}{r-1}$

where a is the first term and r the common ratio

Here r = 5 and a has to be found, thus

$S_{6}$ = $\frac{a(5^6-1)}{5-1}$, so

$\frac{a(15625-1)}{4}$ = 15624

Multiply both sides by 4

15624a = 62496 ( divide both sides by 15624

a = 4