You have a choice of boats to make a trip across a lake with a
240 kg load of supplies for your vacation cabin. You and your
friend both have masses of 80 kg. Since the smaller boats are less
expensive to rent, and you want to keep it for several days, you
chose the smallest one that will safely ferry your load. Be a good
engineer! Allow a safety factor of 2x, such that the boat can
support twice its weight and the load. Knowing the density of water
is 1000 kg/m3, which one do you choose?