Two families ordered three basic food items from their local shop. The Jones family ordered 1 bag of sugar, 4 cartons of milk and 3 loaves of bread. The Singh family ordered no sugar, 3 cartons of milk and 5 loaves of bread. Their orders can be represented by the matrix A where A = ( 1 0 ) ( 4 3 ) ( 3 5 ) The cost of a bag of sugar is 80 cents, the cost of a carton of milk is 50 cents and the cost of a loaf of bread is 40 cents. This information can be represented by the matrix B where B = (80 50 40).

1. (a)Work out BA.[2]
2. (b)What does the matrix BA represent?[1]