Rajesh goes to his office at the speed of 25 km/hr and returns to his home at the speed of 20 km/hr. If he takes total 9 hours, then what is the distance between his office and home?

Let the distance between his home and his office = x km
Time taken to travel from his home to office = $$\dfrac{x}{25}$$ hours

Time taken to travel from his office to home = $$\dfrac{x}{20}$$ hours
Total time = $$\dfrac{x}{25}+\dfrac{x}{20} = \dfrac{5x+4x}{100} = \dfrac{9x}{100}$$ hours
Given, $$\dfrac{9x}{100} = 9$$
=> $$9x = 900$$
=> $$x = 100$$
Therefore, Distance between his home and his office = 100 km.