51.6/(3.4-1.25x0.8)
=51.6/[3.4-1.25x(4/5)]
=51.6/[3.4-0.25x4]
=51.6/[3.4-1]
=51.6/2.4
=516/24
=(480+36)/24
=20+36/24
=20+(24+12)/24
=20+1+12/24
=21.5