9709 P62 - Jun 2016 - Q2
3309
When visiting the dentist the probability of waiting less than 5 minutes is 0.16, and the probability of waiting less than 10 minutes is 0.88.
(i) Find the probability of waiting between 5 and 10 minutes.
A random sample of 180 people who visit the dentist is chosen.
(ii) Use a suitable approximation to find the probability that more than 115 of these people wait between 5 and 10 minutes.
