12% of voters in a recent election voted on the greens candidate,

if 10 people were randomly selected
what is the probability that exactly 4 people voted for the green candidate.

Try the binomial probability formula:

P(x) = nCx * p^x * q^(n-x)

Note: * means to multiply; ^ means raised to the power of.

x = 4
n = 10
p = .12
q = 1 - p

I'll let you substitute the values and take it from here.