c) A sales man has the following record of sales during three months for three items A, B and C which have different rates of commission

Months	Sales in units A	Sales in units B	Sales in units C	Total Sales (Ksh.)
January	90	100	20	800
February	130	50	30	900
March	60	100	40	850

Let X1, X2 and X3 be the selling price unit in sh. on item A, B and C respectively.

d) Formulate a system of simultaneous equations for the above information. (3 marks)

e) Use matrix algebra to determine the selling price per unit of each item. (3 marks)