Max worked at Brampton Brick for his coop placement. His job was to determine the concentration of gravel in concrete mixture supplied by the Halton Concrete company. if the concrete has less than 5% cement, it has to be returned. Max collected a 15.850 lb sample of the concrete mixture. When he analysed it, he found that it contained:4.877 lb of sand, 7.316 lb of gravel and 1.219 lb of water and the rest was cement. What is the percent of cement in the concrete mixture? does it need to be returned