Translate to a system of equations and solve.
1. The sum of two numbers is 27. One number is 3 more than the other. Find the numbers.

12 and 15

Step-by-step explanation:

Let the numbers be called x and y.  We know from the first sentence that:

x + y = 27.

From the second sentence we know that x + 3 = y. (In this problem it does not matter which is x and which is y.)

Substituting in x + 3 into the first equation, we have

x + x + 3 = 27

2x + 3 = 27

2x + 3 - 3 = 27 - 3

2x = 24

x = 12

y = x+ 3 = 15

Check: does x + y = 27?  Yes, 12 + 15 = 27

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! )