a) Mean payoff = 0.5*2+0.5*0.4 million=1.2 million
b (Standard deviation = [ 0.5*(2-1.2)^2+ 0.5*(0.4-1.2)^2]^0.5= 0.8 million
c) Four outcomes are
P (both are not caught) = 0.9^2=0.81
P (Serene is caught and Venus is not caught)=0.9*0.1=0.09
P (Venus is caught and Serena is not caught) =0.1*0.9=0.09
P (both caught) =0.1*0.1=0.01
d) P (at least one fails) = 0.09+0.09=0.18