Bruce is going to call one person from his contacts at random. he has 25 total contacts. 20 of those contacts are from his neighborhood. what is the chance he doesn't call someone from his neighborhood

1/5 is the chance to call from his neighborhood.

Step-by-step explanation:

Bruce is going to call a person from his contacts at random.

Out of 25 contacts 20 contacts were from his neighborhood.

Therefore chance to call someone from his neighborhood is 20/25 = 4/5

Now chance that he doesn't call from neighborhood will be = 1 - chance to call from his neighborhood = 1 - (4/5) = 1/5.

1/5 is the answer.

hello from mrbilldoesmath!

answer:

a(n) - a(n-1) -3

discussion:

this ones a bit interesting. given a(n) = 5 - 3n consider this:

a(n-1) = 5 - 3(n-1)

          = (5 - 3n) + 3             => but a(n) = 5 - 3n, the first term

          = a(n)   + 3                 => subtract 3 from both sides

a(n-1) -3 = a(n)  

or

a(n) - a(n-1) -3

you,

mrb