Ravi decided to cover a distance of 24 km in 2 hours 24 minutes. Further he decided to cover the initial one-third of the total distance at 8 km/hr and the remaining at some different speed. What is the speed (in km/hr) of Ravi after one-third distance is covered?

Correct option is A

Given:
Total distance = 24 km
Total time = 2 hours 24 minutes =$$\frac {12}5$$​ hours
Initial one-third distance = 8 km
Speed for first one-third distance = 8 km/hr
Formula Used:
Time = Distance / Speed
Total Time = Time₁ + Time₂
Solution:
Time taken to cover first 8 km = $$\frac 88$$​= 1 hour
Remaining distance= 24 − 8= 16 km
Remaining time=$$\frac{12}5 − 1 = \frac75$$​ hours
Let the speed for remaining distance be x km/hr.
​$$x = 16 \div \left(\frac{7}{5}\right) \\ x = \frac{16 \times 5}{7} \\\ \\x = \frac{80}{7} \\\ \\ x = 11\frac{3}{7}\ \text{km/hr} \\$$​​
Exam Hall Method: