Question 770803
The formula needed is P(X=r)=n{{{C[r]}}}{{{p^r}}}{{{q^(n-r)}}}
where n{{{C[r]}}} = {{{n!/(r!(n-r)!)}}}
P(X<3)
=P(X=0)+P(X=1)+P(X=2)
=[15{{{C[0]}}}{{{(0.16^0)(0.84^(15-0))}}}]+[15{{{C[1]}}}{{{(0.16^1)(0.84^(15-1))}}}]+[15{{{C[2]}}}{{{(0.16^2)(0.84^(15-2))}}}]
=[{{{1*1(0.84^15)}}}]+[{{{15*0.16(0.84^14)}}}]+[{{{105*0.16^2(0.84^13)}}}]
={{{0.07315+0.2090+0.2787}}}
={{{0.5609}}}