A man has to cover a distance of 519 km in 7 hours. If he covers two-third of this distance in 5/7 of the time, then what should his speed (in km/hr) be to cover the remaining distance in the time left?​

Correct option is A

Given:

Total distance = 519 km

Total time = 7 hours

Distance covered in the first part = $$\frac{2}{3}$$​ of 519 km

Time taken for the first part = $$\frac{5}{7}$$ of 7 hours

Formula Used:

Remaining distance = Total distance - Distance for first part

Remaining time = Total time - Time for first part

Speed required = $$\frac{\text{Remaining distance}}{\text{Remaining time}}$$​​

Solution:

Distance for the first part = $$\frac{2}{3} \times 519$$​ = 346 km

Time for the first part = $$\frac{5}{7} \times 7$$​ = 5 hours

Remaining distance = 519 - 346 = 173 km

Remaining time = 7 - 5 = 2 hours

Speed required = $$\frac{173}{2}$$​ = 86.5 km/hr

Thus, the man should travel at a speed of 86.5 km/hr to cover the remaining distance in the time left.