Calculating concerntration?

zondi prepares a very accurate solution of calcium hydroxide,Ca(OH)2 for his experiment.he weigh 2.74g of the salt Ca(OH)2 and transf2,74g of Ca(OH)2 is weight and transferred into a 100ml volumetric flask.thabo adds water to the salt and shakes the flask to dissolve the salt and then adds more water untill the mark.the volumetric flask now contains 100.0 solution.romeo diluted his solution by transferring 20ml of it into a 100ml volumetric flask,calculate concerntration of romeo's dilute solution in grams solute per 100 ml solution