You are doing yardwork with a friend. you can finish mowing the lawn in 57 minutes, while your friend can do the same amount of work in 54 minutes. how long will it take to complete the job if you work together? round your answer to the nearest whole number.

28 minutes

Step-by-step explanation:

Speed = distance / time

Your speed is 1 lawn / 57 minutes.  Your friend's speed is 1 lawn / 54 minutes.  Working together, your combined speed is:

1/57 + 1/54

So the time it takes working together is:

Speed = distance / time

1/57 + 1/54 = 1 / t

t = 27.7 minutes

Rounded to the nearest whole number, it takes 28 minutes.

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! )

i just took the test, the correct answer is .. 31.5 in.