9709 P63 - Jun 2010 - Q3
3071
Christa takes her dog for a walk every day. The probability that they go to the park on any day is 0.6. If they go to the park there is a probability of 0.35 that the dog will bark. If they do not go to the park there is a probability of 0.75 that the dog will bark.
(i) Find the probability that they go to the park on more than 5 of the next 7 days.
(ii) Find the variance of the number of times they go to the park in 30 days.
