Left panels: histograms of the distance in the (r − i) color of the PMS stars from the mean ridge line of the bluest population, as obtained with our Monte Carlo simulations (black, heavy lines) and as observed (red). Right panels: corresponding assumed distribution of the mass ratios of all the binaries in our simulated sample. The χ² of each solution is also indicated in the left panels. Both top panels correspond to the canonical cases of 40% multiplicity and a uniform mass ratio distribution.