1. 4 A box contains 300 discs of different colours. There are 100 pink discs, 100 blue discs and 100 orange discs. The discs of each colour are numbered from 0 to 99. Five discs are selected at random, one at a time, with replacement. Find (i) the probability that no orange discs are selected. [3]

(ii) the probability that exactly 2 discs with numbers ending in a 6 are selected. [4]

(iii) the probability that exactly 2 orange discs with numbers ending in a 6 are selected. [4]

(iv) the mean and variance of the number of pink discs selected. [8]

1. 5 The mean number of defective batteries in packs of 20 is 1. 6. Use a binomial distribution to calculate the probability that a randomly chosen pack of 20 will have more than 2 defective batteries