Question

A seesaw is 4 meters long and is pivoted in the middle. There is a 350 N child on the left end. Where will a 540 N person have to sit to balance the seesaw?

Answer 1

Assume a distance of d from the fulcrum. Take moments about the fulcrum:
350*2-540d=0
d=1.296 m

Answer 2

100