Ireally need an answer asap! 15 points
sally can paint a room in 7 hours and john can paint the same room in 10 hours. how long should it take sally and john to paint the room together?

It would take them 8.5 hours.

Explanation:

Since they are painting the room together, they would basically each paint half of the room. So if they were painting half of the room each, it would take them half of the time that it would

normally take each of them. Half of Sally's time is 3.5 hours. And half of John's time is 5 hours. When you add them together, you get 8.5 hours.

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! )

4

step-by-step explanation:

im pretty sure it's 4 beacsue 8/2 equals 4