£5 = 500 p1 Pencil = 8p1 ruler= 30pIf she is buying 15 Pencil , it will be= 8 *15= 120p, 380 p remains ( 500p-120p= 380p) 360p / 30 = 12 rulers this will give you a change of 20 p , 20/8 ( price for a pencil) = 2 pencilsHence, Nadia will buy 17 pencil, 12 rulers and will keep a change of 4p.