This is a linear programming problem. You may find this helpful.
If jones utility function is expressed as U= 5logx1 + 3logx2+2logx3. where x1,x2,x3 represents football,jersey and Boot respectively, if he is faced with a constraint expressed as 10x1 + 2x2 +4x3 - 100 = 0. Assist him to determine the optimum amount of Jersey, Boot and Football he should purchase.