To find the weight of the oldest gorilla in the zoo, b, you can use the equation 2b – 15 = 605. Plug the weight of each gorilla into the equation to check which value makes the equation true.

Sophia | 318 |  2(318) - 15 | False

George | 417 |  2(417) - 15 | False

Nancy | 310 | 2(310) - 15 | True

Hank | 136 |  2(136) - 15 | False

Paula | 62 | 2(62) - 15 | False

Gavin | 24 |  2(24) - 15 | False

Step-by-step explanation:

With Sophia, her equation is 2(318) - 15. That equals 621, not 605.

With George, his equation is 2(417) - 15. That equals 819, not 605.

With Nancy, her equation is 2(310) - 15. That equals 605.

With Hank, his equation is 2(136) - 15. That equals 257, not 605.

With Paula, her equation is 2(62) - 15. That equals 109, not 605.

With Gavin, his equation is 2(24) - 15. That equals 33, not 605.

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! )