9709 P61 - Jun 2015 - Q4
2617
A survey is undertaken to investigate how many photos people take on a one-week holiday and also how many times they view past photos. For a randomly chosen person, the probability of taking fewer than 100 photos is \(x\). The probability that these people view past photos at least 3 times is 0.76. For those who take at least 100 photos, the probability that they view past photos fewer than 3 times is 0.90. This information is shown in the tree diagram. The probability that a randomly chosen person views past photos fewer than 3 times is 0.801.
(i) Find \(x\).
(ii) Given that a person views past photos at least 3 times, find the probability that this person takes at least 100 photos.
