A train travels first 800 kms at an average rate of 150 kmph and further travels the same distance at an average rate of 120 kmph. Determine the average speed of the train over the whole journey.
Answers
For the first 800 kms.
Average speed = 150 kmph.
Time taken to cover the distance = ( Distance / Speed )
( 800 / 150 ) = 5 1/3 hours.
For the next 800 kms.
Average speed = 120 kmph.
Time taken to cover the distance = ( Distance / Speed )
( 800 / 120 ) = 6 2/3 hours.
Total distance covered = 1600 kms.
Total time taken = 5 1/3 hours + 6 2/3 hours.
= 12 hours.
Average speed for the journey = ( Total distance / Total time ) = 133 1/3 kmph.
For the first 800 kms.
Average speed = 150 kmph.
Time taken to cover the distance = ( Distance / Speed )
( 800 / 150 ) = 5 1/3 hours.
For the next 800 kms.
Average speed = 120 kmph.
Time taken to cover the distance = ( Distance / Speed )
( 800 / 120 ) = 6 2/3 hours.
Total distance covered = 1600 kms.
Total time taken = 5 1/3 hours + 6 2/3 hours.
= 12 hours.
Average speed for the journey = ( Total distance / Total time ) = 133 1/3 kmph.