Question 1056956
Expected value is 0.10*30=3 window frames x*(p(x))
probability of 0 is 0.90^30=0.0424
probability of 1 is 30*0.9^29*0.10=0.1413
probability of 2 is 435*0.9^28*0.10^2=0.2277
probability of 3 is 4060*0.9^27*0.1^3=0.2361
They add to 0.6051
More than 3 is 1-0.6051=0.3949, using the complement rule.