An ideal speing, with a pointer attached to its end, hangs next to a scale. With a 100 N weight attached and in equilibrium, the pointer indicates `40` on the scale as shown. Using a 200 N weight instead results in 60 on the scale. Using an unknown weight `X` instead results in `30` on the scale. Find the value of `X` is

Explanation

`40=L+(100)/(K)implies60=L+(200)/(K)`
`K=5` and `L=20`
Now `30=20+(x)/(5)impliesx=50`