6. Determine if the sequence is arithmetic or geometric, and the common ratio or
difference.
-4,-2.5, -1, 0.5, 2,
A. Arithmetic; d = 1.5
B. Arithmetic; d = 2
C. Geometric; r = 0.5
D. Geometric; r = 2

A. Arithmetic; d = 1.5

Step-by-step explanation:

-4, -2.5, -1, 0.5, 2

Looking at the sequence, we can see that the numbers increase. This means our common ration or difference will be positive.

Let's look at common ratios first.

To find the common ratio, divide one term from the term after it.

r = a₂ ÷ a₁

r = -2.5 / -4

Divide.

r = 0.625

To see if this is the common ratio, we want to test this with the other numbers of the sequence.

r = a₃ ÷ a₂

r = -1 / -2.5

r = 0.4

This is not consistent; therefore our sequence is not geometric.

Let's look at common differences next.

To find the common ratio, subtract one term from the term after it.

r = a₂ - a₁

r = -2.5 - (-4)

Simplify.

r = -2.5 + 4

Add.

r = 1.5

To see if this is the common difference, we want to test this with the other numbers of the sequence.

r = a₃ - a₂

r = -1 - (-2.5)

Simplify.

r = -1 + 2.5

r = 1.5

This is consistent; therefore we have found our common difference of this arithmetic sequence.

A. Arithmetic; d = 1.5

Hope this helps!

the answer   is 200

step-by-step explanation:

this is a problem about poisson probabilities.   i don't know if you've

already studied poisson distributions, or if you have a place to look

to read more about the subject.  

here's how you can see a poisson distribution coming.   when there are

a lot of events that may happen at any time (or any place), and when

you're counting how many of them happen at a particular time (or a

particular place), and each event is independent of the others, then

the result is a poisson distribution.   this is roughly true for the

chocolate chips; one chip being in a cookie has only a small effect on

the probability that another chip will be in the cookie.

once you know you have a poisson distribution, you know a lot.   there

is only one parameter to a poisson distribution, so if you know the

mean, you know everything.   the form of the distribution is

  probability of n chips = {[e^(-x)]*(x^n)} / (n! )