Answer:
-0.9090... can be written as
.
Explanation:
Any <em>repeating </em>decimal can be written as a fraction by dividing the section of the pattern to be repeated <em>by </em>9's.
We can start by listing out
0.909090... = 9/10 + 0/100 + 9/1000 + 0/10000 + 9/100000 + 0/1000000 + ...
Now. we let this series be equal to x, that is
= 9/10 + 0/100 + 9/1000 + 0/10000 + 9/100000 + 0/1000000 + ...
Now, we'll multiply both sides by 100
.
= 90 + 0 + 9/10 + 0/100 + 9/1000 + 0/10000 + ...
Then, subtract the 1st equation from the second like so:
= 90 + 0 + 9/10 + 0/100 + 9/1000 + 0/10000 + 9/100000 + 0/1000000 + ...
= - 9/10 - 0/100 - 9/1000 - 0/10000 - 9/100000 - 0/1000000 - ...
And we end up with this:

Finally, we divide both sides by 99 in order to isolate x and get the fraction we're looking for.

Which can be reduced and simplified to

Hope this helps!
The bacteria grow from 1,000 bacteria into 12,500 bacteria in 12 hours. The exponent function would be
:an= ao(1+r)^t12.500= 1,000(1+r)^121,000(12.5)= 1,000(1+r)^1212.5= (1+r)^121+r= 1.23427r= 0.23Number of bacteria after 20hr would be:an= ao(1+r)^tan= 1,000(1+0.23)^20an= 1,000(62.821 )an= 62,821