X has mean 108*0.04=4.32 and variance 108*0.04*0.96=4.147 So total (T) over 60 days has mean 60*4.32=259.2 and variance 60*4.147=248.82 and standard deviation root248.82=15.77. For mean at most 4 we want T to be at most 240

Using normal approximation P(T<240)=P(Z<(240-259.2)/15.77) That is want Z<-1.218 Using tables this is 1-0.8884=0.112