Their selling prices are ` 80, ` 60 and
` 40 each respectively Find the total amount the bookshop will receive from
selling all the books using matrix algebra Assume X, Y, Z, W and P are matrices of order 2 × n, 3 × k, 2 × p, n × 3 and p × k,
respectively Choose the correct answer in Exercises 21 and 22