A product is sold in packets whose masses are normally distributed with a mean of 1.42 kg and a standard deviation of 0.025 kg.

(a) Find the probability that the mass of a packet, selected at random, lies between 1.37 kg and 1.45 kg.

(b) Estimate the number of packets, in an output of 5000, whose mass is less than 1.35 kg. (C)