A man plans to travel a total distance of 60 km in 6 hours, covering part of the journey on foot and the rest by bicycle. His walking speed is 6 km/hr, and his cycling speed is 12 km/hr. How much distance (in km) does he cover on foot?

Correct option is D

Given:
Total distance = 60 km
Total time = 6 hours
Formula Used:
Distance = Speed × Time
Solution:
Let distance covered on foot = x km
Distance by bicycle = (60 - x) km
Time on foot =$$\frac {x}{6}$$​
Time on bicycle = $$\frac {60 - x}{ 12}$$​​
According to question:
​$$\frac{x}{6}+\frac{60-x}{12}=6 \\\ \\\Rightarrow \frac{2x+60-x}{12}=6 \\\ \\\Rightarrow \frac{x+60}{12}=6 \\\ \\\Rightarrow x+60=72 \\\ \\\Rightarrow x=12 \\\ \\$$​​