A uniform metre rule is balanced on a fulcrum placed at the 35cm mark by suspending a mass of 120g at the 10cm mark. Calculate the mass of the metre rule.

A. 60g
B. 80g
C. 120g
D. 200g

Correct Answer: Option D

D. 200g

Explanation

Clock-wise moment = Anti-clock wise

15 x m = 5 x 10

m = 200g