Let time Marco takes, alone, be M Then time Cliff takes, alone, = 2M Therefore, Marco can doof job in 1 hour, while Cliff can do of job in 1 hour With both taking 5 hours to do entire job, working together, we get: 10 + 5 = 2M ------ Multipluing by LCD, 10M 15 = 2M Time Marco takes, doing entire job alone, or