A man travelled 80 km in 7 hours some of which he travelled on foot at the ratio of 8 km/hr and some of the journey by bicycle at the rate of 16 km/hr. How much distance did he travel on foot?

Correct option is A

Given:

Total distance travelled = 80 km

Total time taken = 7 hours

Speed on foot = 8 km/h

Speed on bicycle = 16 km/h

Concept Used:

Let the distance travelled on foot be x km.

Therefore, the distance travelled by bicycle = (80 - x) km.

Time taken on foot =  $$\frac{Distance }{ Speed} = \frac{x }{ 8} hours.$$​​

Time taken by bicycle = $$\frac{Distance }{ Speed} = \frac{(80 - x) }{16}$$​ hours.

Total time = Time on foot + Time by bicycle = 7 hours.

Solution:

The total time is given by:

​$$\frac{x }{8} +\frac{ (80 - x) }{ 16} = 7$$​​

2x + (80 - x) = 112

2x + 80 - x = 112

x = 32

Therefore, the man travelled 32 km on foot.