A train travels at a speed of `60 km h^(-1)` for `0.5 h, 24 km h^(-1)` for the next 0.25 h and then `72 kmh^(-1)` for the next 0.75 h. Calculate the total distance covered by the train and its average speed.

Explanation

Average speed `= ("Distance")/("Time")`
`therefore` Distance = Average speec `xx` Time
`= 60 km h ^(-1) xx 0.5 h = 30 km …(1)`
`therefore ` Distance = Average speed `xx` Time
`= 24 km h ^(-1) xx 0.25 h = 6 km …(2)`
`therefore` Distance = Average speed `xx` Time
`= 72 km h ^(-1) xx 0.75 h = 54 km ...(3)`
From (1), (2) and (3),
the total distance covered `= (30 + 6 + 54) km = 90 km`
Total time take `= (0.5 + 0.25 + 0.75) h = 1. 50 h `
Average speed `= ("Total distance covered")/("Total time taken")= (90 km)/(1.50 h) = 60 km h ^(-1)`
The total distance covered by the train `= 90 km.`