A man walks to a viewpoint and returns to the starting point by his car maintaining constant speed and thus takes a total time of 3 hours 30 minutes. He would have gained 3 hours by driving both ways. How long would it have taken for him to walk both ways with same walking speed?

Correct option is A

Given:

Time taken by man by walking and returning by car at constant speed =3 hours and 30 minutes

Time taken by man driving both sides = 30 minutes

Formula Used:

Time =$$\frac{Distance}{Speed}$$​​

Solution:

Let the distance be x

Let speed of walking of man be s and speed of riding be r

Then

​$$\frac{x}{s} +\frac{x}{r} = 3hour30min =210min$$​  ….(1)

​$$\frac{2x}{r} = 30min$$​

​$$\frac{x}{r} = 15min$$​    …..(2)

Putting the value of $$\frac{x}{r}$$​ in eq(1)

​$$\frac{x}{s} =210 min - 15min$$​​

​$$\frac{x}{r} = 195min$$​​

Total time taken going and returning by walk =$$2 \times 195$$ = 390 min = 6 hours 30 min