physics
posted by Ken .
a 200 gram mass is balanced at one end of a meterstick and a 100 gram mass is at the other. the center of mass is 36.75 cm from the 200 gram mass.
What is the mass of the meterstick?
Thank you for you help

Don't you mean the fulcrum was 36.75 cm from the end with the 200 g mass?
Or do you mean the center of mass of meterstick and both weights (together) is at 36.75 cm? That would also make sense.
Whether it is balanced or not depends upon where the fulcrum is.
The center of mass of the meter stick is probably at the 50 cm mark.
Set the total moment about the fulcrum equal to zero and solve for the mass of the meterstick. 
The fulcrum is at 36.75

Set the total moment about the fulcrum equal to zero and solve for the mass M of the meterstick. (You can omit the g factors, which cancel out. I will leave mass in grams, and distances in cm).
200*36.75 + M*13.25 = 100*63.25
M = 79.23 g