A train runs at a speed of 111 kmph to cover a distance of 222 km and then at a speed of 86 kmph to cover a distance of 258 km. Find the average speed of the train for the entire distance.

Correct option is B

Given:
First segment: Speed = 111 km/h, Distance = 222 km

Second segment: Speed = 86 km/h, Distance = 258 km

Formula Used :
​$$\text{Average speed} = \frac{\text{Total Distance}}{\text{Total Time}}$$​

Solution:​ 

Total Distance = 222 km + 258 km = 480 km​

​$$\text{Time}_1 = \frac{\text{Distance}_1}{\text{Speed}_1} = \frac{222\,\text{km}}{111\,\text{km/h}} = 2\,\text{hours}$$​

​$$\text{Time}_2 = \frac{\text{Distance}_2}{\text{Speed}_2} = \frac{258\,\text{km}}{86\,\text{km/h}} = 3\,\text{hours}$$ 

​$$\text{Total Time} = \text{Time}_1 + \text{Time}_2 = 2\,\text{hours} + 3\,\text{hours} = 5\,\text{hours}$$​

​$$\text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}} = \frac{480\,\text{km}}{5\,\text{hours}} = 96\,\text{km/h}$$

Option (B) is right.