Question

A train covers the first 60 km of its journey at a speed of 80 km/h , the next 90 km at a speed of 100 km/h, and the rest of its 330-km journey at a speed of 120 km/h . Find the total time taken to complete its journey. Also, find its average speed.​

Answer 1

Step-by-step explanation:

Total time taken by the train during its whole journey

=

$( \frac{60}{80} + \frac{90}{100} + \frac{330}{120} ) hours \\ = > \frac{900 +1080 + 3300 }{1200} hours \\ = > \frac{5280}{1200} hours \\ = > 4.4hours$

Therefore average speed

=

$\frac{total \: distace}{total \: time} = \frac{(60 + 90 + 330)}{4.4} km.h {}^{ - 1} \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = > 109.09km.h {}^{ - 1}$

Answer 2

Answer:

Step-by-step explanation:

Total time taken by the train during its whole journey

=

Therefore average speed

=