Given:
The geometric sequence is:

1 -4
2 20
3 -100
To find:
The explicit formula and list any restrictions to the domain.
Solution:
The explicit formula of a geometric sequence is:
...(i)
Where, a is the first term, r is the common ratio and
.
In the given sequence the first term is -4 and the second term is 20, so the common ratio is:



Putting
in (i), we get
where 
Therefore, the correct option is B.
Answer:
0.2103 = 21.03% probability that, in any seven-day week, the computer will crash less than 3 times.
Step-by-step explanation:
In a Poisson distribution, the probability that X represents the number of successes of a random variable is given by the following formula:

In which
x is the number of sucesses
e = 2.71828 is the Euler number
is the mean in the given interval.
Mean of 0.6 times a day
7 day week, so 
What is the probability that, in any seven-day week, the computer will crash less than 3 times? Round your answer to four decimal places.

In which




So

0.2103 = 21.03% probability that, in any seven-day week, the computer will crash less than 3 times.
Karim=4,8km,12km,16km Shawn=3,6km,9km,12km
It would be 13.50 because 50% off of 18$ is 9$ but it’s not 50% off itS 25% off so If you take the 50% Off price of 9$ and add 4.50 (One more 1/4th) you get $13.50
Let x represent the # of people in sid’s group: 200 - (16.25x + 6.50x) = 18.25
200 - 22.75x = 18.25
-22.75x = -181.75
x = about 8
if Sid is not included in the group, i think the answer is D. 7, but im not sure