b)ma=[5,8(3)+2,1(6)]:2
=[583-58 supra 90 + 216-21 supra 90]:2
=[525 supra 90+195 supra90]:2
=720supra 90 :2
=8:2
=4
c)ma=[514-51supra90+857-85supra90+423-42supra90]:3
=[463supra90+772supra90+381supra90]:3
=1616supra90:3
=1616supra90x1supra3
=1616supra270