1. **State the problem:** Sally can paint a house in 4 hours, John can paint the same house in 6 hours. We want to find how long they take together to paint one house. 2. **Find individual rates:** Sally's rate is $\frac{1 \text{ house}}{4 \text{ hours}}=\frac{1}{4}$ houses/hour. John's rate is $\frac{1 \text{ house}}{6 \text{ hours}}=\frac{1}{6}$ houses/hour. 3. **Add the rates to find combined rate:** Combined rate = $\frac{1}{4} + \frac{1}{6}$ houses/hour. To add these fractions, find common denominator 12: $$\frac{1}{4} = \frac{3}{12}, \quad \frac{1}{6} = \frac{2}{12}.$$ So combined rate = $\frac{3}{12} + \frac{2}{12} = \frac{5}{12}$ houses/hour. 4. **Find time taken together:** Time = $\frac{1 \text{ house}}{\text{rate}} = \frac{1}{\frac{5}{12}} = \frac{12}{5} = 2.4$ hours. **Final answer:** It takes Sally and John working together 2.4 hours to paint the house.