Dawid rolls a fair six-sided dice 10 times. He records, X, the number of times the dice lands on a prime number. a Define a suitable distribution to model X and write down two assumptions that are required for the distribution to be valid. (2 marks) (2 marks) b Find the probability that Dawid rolls 4 prime numbers. He repeats the experiment 7 times. e Find the probability that he rolls 4 prime numbers exactly twice. (3 marks)