one sheet of 8 1/2 by 11" paper weighs 4.5 x 10^-3 kg. A school is expecting a delivery of 100 cases of paper which include a total of 5 x 10^5 pieces of paper. How much does all the paper in the cases weigh?

yep

Step-by-step explanation:

I just weighed a standard #10 business envelope 4 1/4″ x 9 1/2″) along with a letter-sized sheet (8 1/2″ x 11″) of 24# paper on my postal scale.

0.4 oz. Well under the 1 ounce that is the maximum for a single first-class stamp in the US.

You actually would need to have more than 4 sheets of paper to top an ounce so you can get pretty wordy about it

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! )

stops on an even number.