23 In the diagram, OB=( 12 6). (a) Show that the gradient of OB=1/2. (b) AP is parallel to OB and AP=(p 2) (i) Find the value of p. (ii) Write down the value of AP/OB. (c) AQ is perpendicular to OB. (i) Write down the gradient of AQ. (ii) Given that AQ=(3 q), find the value of q.