Individual ratesMaria: 1 manuscript in 6 days → rate = 1/6 per dayJuan: 1 manuscript in 4 days → rate = 1/4 per daySet up the rational equationLet T = time (in days) working together.Combined rate = 1/T.Equation: 1/T = 1/6 + 1/4SolveFind sum: 1/6 + 1/4 = 2/12 + 3/12 = 5/12So 1/T = 5/12 → T = 12/5 = 2.4 daysInterpretationWorking together, Maria and Juan finish in 2.4 days, which is 2 days, 9 hours, 36 minutes (0.4 day × 24 hours = 9.6 hours).