Match color balance to an rgb value?

[glewey]

 

Help! How would I change the color balance of something like the above image to correspond to an RGB value? The color balance tool is 0-100 while RGB values are obviously 0-255. 

[Stephen Marsh]

Place color samplers (i) onto the image, evaluate the info panel results via RGB display..The sampler size can be adjusted to a larger area to average out the readings.