1. **State the problem:** A rower travels upstream at 6 km/h and back downstream at 10 km/h. The total journey takes 48 minutes. We need to find the distance upstream. 2. **Define variables:** Let the distance upstream be $d$ km. 3. **Write expressions for time:** - Time upstream = $\frac{d}{6}$ hours - Time downstream = $\frac{d}{10}$ hours 4. **Total time given:** 48 minutes = $\frac{48}{60} = 0.8$ hours 5. **Set up equation:** $$\frac{d}{6} + \frac{d}{10} = 0.8$$ 6. **Find common denominator and combine:** $$\frac{5d}{30} + \frac{3d}{30} = 0.8$$ $$\frac{8d}{30} = 0.8$$ 7. **Simplify fraction:** $$\frac{\cancel{8}d}{\cancel{30}} = 0.8 \Rightarrow \frac{4d}{15} = 0.8$$ 8. **Solve for $d$:** Multiply both sides by 15: $$4d = 0.8 \times 15$$ $$4d = 12$$ Divide both sides by 4: $$d = \frac{12}{4} = 3$$ 9. **Answer:** The rower traveled 3 km upstream.