A man travelled a distance of 35 km in 5 hours. He travelled partly on foot at the rate of 4 km/h and the rest on bicycle at the rate of 9 km/h. The distance travelled on foot is:

Let the distance travelled on foot = d

$$\Rightarrow$$  Distance travelled on bicycle = 35 - d

Speed of the man on foot = 4 km/h

Time taken by the man on foot = $$\frac{d}{4}$$

Speed of the man on bicycle = 9 km/h

Time taken by the man on bicycle = $$\frac{35-d}{9}$$

Total time taken by the man = 5 hours

$$\Rightarrow$$  $$\frac{d}{4}+\frac{35-d}{9}=5$$

$$\Rightarrow$$  $$\frac{d}{4}+\frac{35}{9}-\frac{d}{9}=5$$

$$\Rightarrow$$  $$\frac{9d-4d}{36}=5-\frac{35}{9}$$

$$\Rightarrow$$  $$\frac{5d}{36}=\frac{10}{9}$$

$$\Rightarrow$$  d = 8 km

$$\therefore\ $$Distance travelled on foot = 8 km

Hence, the correct answer is Option A