Question

Two shopkeepers, Juma and Wan bought some items from a wholesaler. Juma bought 18 loaves of bread, 40 packets of milk and 5 bars of soap while Wan bought 15 loaves of bread, 30 packets of milk and 6 bars of soap. The price of a loaf of bread, a packet of milk and a bar of soap were sh 45, sh 50 and sh 150 respectively.

a.
(I) the number of items bought by Juma and Wan using a 2 * 3 matrix.
18l 40m 5b
15l 30m 6b

(ii) the price of the items bought a 3 * 1 matrix
45
50
150

(b) Use the matrices in (a) above to determine the total expenditure incurred by each person and hence the difference in their expenditure.

Answer 1

Your matrices are correct.

As for determining the total expenditure, multiply both the matrices together.
If you multiply a 2*3 with a 3*1 matrix (in that order), the product will be a 2*1 matrix. It will have two entries, each giving you the total expenditure of one school.