In a certain region, the number of children who have been vaccinated against rubella is twice the number who have been vaccinated against mumps. the number who have been vaccinated against both is twice the number who have been vaccinated only against mumps. if 5,000 have been vaccinated against both, how many have been vaccinated only against rubella?

10,000

Step-by-step explanation:

"The number who have been vaccinated against both is twice the number who have been vaccinated only against mumps."

Let b = number of children vaccinated against both.

Let m = number of children vaccinated only against mumps.

b = 2m

"If 5,000 have been vaccinated against both"

5000 = 2m

m = 2500

5000 children are vaccinated against both.

2500 children are vaccinated only against mumps.

The total number vaccinated against mumps is the number vaccinated only against mumps plus the number vaccinated against both:

2500 + 5000 = 7500

"the number of children who have been vaccinated against rubella is twice the number who have been vaccinated against mumps."

total number of children vaccinated against rubella = 2 * 7500 = 15,000

5000 of those children are vaccinated against both.

15,000 - 5000 = 10,000

10,000 children are vaccinated only against rubella.

10,000

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! )

step-by-step explanation:

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