A manufacturer of metal pistons finds that on the average, 15% of his pistons are rejected because they are either oversize or undersize. What is the probability that a batch of 10 pistons will contain: (Express your answers correct to 4 decimal places): a) At least 2 rejects? [3 marks] b) Exactly 5 rejects? [2 marks] c) Find the mean [1 mark]