You ask a neighbor to water a sickly plant while you are on vacation. Without water the plant will die with probability 0.75. With water it will die with probability 0.4. You are 82 % certain the neighbor will remember to water the plant. You come back from the vacation and the plant is dead. What is the probability the neighbor forgot to water it?

0.2915

Step-by-step explanation:

Let W represent water and D represent Dying probability

W = water

D = die

->If with water, it will die with probability 0.4

P(W & D) = 0.82 x 0.4 = 0.328

->Without water the plant will die with probability 0.75

P(W ' & D) = 0.18 x 0.75 = 0.135

Taking sum of the above values with water and without water.

P(D) = P(W & D) +  P(W ' & D) = 0.4643

P(W ' | D) = P(W ' & D) / P(D)

= 0.135 /0.463

= 0.2915 ≈ 29.15%

Thus, the probability the neighbor forgot to water is 0.2915

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! )

horizontal translation of 2 units in the positive x direction

followed by

vertical translation of 3 units in the positive y direction