Number of pallets moved in 4.5 hours = 108
converting 4.5 hours in minutes we get,
4*60 + 0.5*60 = 240+30 = 270 minutes
So, 108 pallets were moved in = 270 minutes
1 pallet was moved in = minutes
As the tie will get over in 2 hours or 2*60 = 120 minutes, the number of pallets that can be moved will be = pallets.
Hence, 48 pallets can be moved before quitting time.