Answer:
please write this question in English then I give answer
Answer:
battery costs: 0.39...............
A geometric series is written as
, where
is the first term of the series and
is the common ratio.
In other words, to compute the next term in the series you have to multiply the previous one by
.
Since we know that the first time is 6 (but we don't know the common ratio), the first terms are
.
Let's use the other information, since the last term is
, we know that
, otherwise the terms would be bigger and bigger.
The information about the sum tells us that

We have a formula to compute the sum of the powers of a certain variable, namely

So, the equation becomes

The only integer solution to this expression is
.
If you want to check the result, we have

and the last term is

We are given a volume of 160 fluid ounces of chemical which is added to a container that holds 120,000 gallons of water. Assuming that the chemical has the same density as water, we just need to convert 120,000 gallons to ounces.
A conversion factor is taken from literature, 1 gallon is equivalent to 128 fluid ounces. So 160 fluid ounces is only 1.25 gallons, thus occupying minimal space in the container. The employee could add more of the chemical in the container. He can actually add 15360000 fluid ounces in total.
Answer: $1800
The theater income will be the total of audience multiplied by the ticket cost. To answer this question, you need to determine the total audience count. Assuming all the seats are occupied then:
Total audience= row of seats x seats/ row = 20x18 people = 360 people
After that the income would be:
Income = audience x ticket cost
Income= 360 people x $5 / people= $1800