A gumball machine has 6 red gumballs, 3 green gumballs, and 5 blue gumballs. What is the
probability that the next gumball that comes
out will be red?
A 1/14
B 1/3
C 3/7
D 3/4

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

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step-by-step explanation: