Question

A uniform rod AB of mass 60g is balanced horizontally about a knife edge at distance of 3cm from end A where a mass of 8.0g having.find the length the rod.

Answer 1

mass 8 grams 3 cm left of pivot

mass 60 grams at L/2- 3 cm right of pivot
so
8 * 3 = 60 [ L/2 - 3 ]
are you sure about the 60 and the 3 ?