# Linear Equation 10

### From Homeworkwiki

**A man covers a distance of 15 km in 3 hours, partly by walking and partly be running.**

**If he walks at 3 km/h and runs at 9 km/h, find the distance covered by running.**

**Solution:**

Let the distance covered by running be x km

Therefore, distance covered by walking (15 - x) km

Therefore, Time taken to cover x km by running = x / 9 hr [since, time = distance / speed ]

and, time taken to cover (15 - x) km by walking = (15 - x) / 3 hr

since, the man covers the total distance in 3 hrs

Therefore, x / 9 + (15 - x) / 3 = 3 [ As total time taken = 3 hrs ]

on solving the above equation, we have

=> x = 9

**Therefore, Distance covered by running = 9 km**