Question

Find the sum of this infinite geometric series.
100+60+36+...

Answer 1

do you know the formula?
see
https://en.wikipedia.org/wiki/Geometric_series#Formula

Answer 2

to use the formula you need to know the "r" which is called the "common ratio"
take the first two terms, 100 and 60
100 * r = 60
divide both sides by 100
r= 60/100
r= 0.6

also, a is the first term. a is 100