All solutions here are SUGGESTED. Mr. Teng will hold no liability for any errors. Comments are entirely personal opinions.

(i)

Let X denote the mass of food content in a type A packet, in grams

Let Y denote the mass of food content in a type B packet, in grams.

(ii)

(iii)

### KS Comments

Students are expected to show the workings for expectation and variance clearly here.