1. The problem statement, all variables and given/known data An ideal spring hangs next to a scale, when a 100N weight the scale reads 40, when a 200N weight is attached it reads 60. Using an unknown weight reads 30. 2. Relevant equations F=-kx 3. The attempt at a solution I attempted to find the value of k for the spring however when calculating k for the 100N it is 2.5N/m and for the 200N it is 3.3N/m which doesn't make sense to me since I would've thought k would be constant. I also tried using F/x=F/x but this also didn't work so I'm completely lost.