Two unfair coin flips, probability of both heads

count=0;
Do[
r=RandomReal[1];
s=RandomReal[1];
If[r<0.4&&s<0.6,count+=1],
10000]
count

Probability of at least two sixes when rolling three fair, standard dice

count=0;
Do[
dice=RandomChoice[Range[6],3];
sixes=Count[dice,6];
If[sixes≥2,count+=1],
10000]
N[count/10000]

Probability that at least 18 out of 3000 people have the same birthday

count=0;
Do[
bdays=RandomChoice[Range[365],3000];
tab=BinCounts[bdays];
If[Max[tab]≥18,count+=1],
10000]
N[count/10000]

bdays=RandomChoice[Range[5],20]
BinCounts[bdays]

Length[%]