Normal model of bottle volumes: probability of rejection, expected number rejected and a conditional probability

A machine fills bottles with a drink. The volume of drink in a bottle is \(V\) millilitres, where \(V\sim\mathrm{N}\left(750,\ 4.2^2\right)\). Any bottle containing less than \(742\) millilitres is rejected.

1. Calculate the probability that a randomly chosen bottle is rejected.[2]
2. A random sample of \(250\) bottles is taken. Estimate how many of these bottles are rejected.[1]
3. A bottle is chosen at random and is found not to be rejected. Calculate the chance that this bottle holds more than \(756\) millilitres.[3]