a 60 kg object is attached to one end of a 40 kg steel tube 2.4 m long. what is the distance from the loaded end to the balance?
I don't know what "to the balance" means. Do you mean the fulcum to the load?
summing moments about the "one end"
down forces=40+60=100kg
up forces at the fulcrum 100kg
summing moments about the end.
40(2.4/2)+60x-100y=0 where x is the distance from the end to the load, and y is the distance from the end to the fulcrum.
summing moments about the fulcrum:
40(1.2-y)=60(y-x) draw the picture to see that.
so you now have two equations, two unknowns, solve for x