Question

A man who weight 90kgf is balanced by a small boy 30kgf who sits metres from the fulcrum of a seesaw. At what distance on the fulcrum is the man sitting

Answer 1

supply the missing distance, and then solve just as you did the last one.

Note that since the man weighs 3 times as much, the boy must sit 3 times farther away from the fulcrum.