Question

on a 100 km track a train moves the first 50 km with a uniform speed of 50 km how fast must the train travel the next 50 km so as to the average speed 50 km per hour from the entire trip??​

Answer 1

I hope you understand thanks

Answer 2

$\huge\bold{\textbf{\textsf{{\color{cyan}{Answer}}}}}$

Average speed =$\frac{Total \: distance \: traveled}{Total \: time \: taken}$

Let's find the time taken by train to travel each part of the distance.

For the first part:

∴ Distance = 100 km

∴ Speed = 50 km/h

Time =

$\frac{Distance}{speed} = 100/s$

Now, as we know that :

Average speed =$\frac{Total \: distance \: traveled}{Total \: time \: taken}$

where, Average speed = 70 km/h

Total distance travelled = 200 km

Total time taken = 2 + 100/s

Substituting these values in the average speed equation, we get:$\frac{Total \: distance \: traveled}{Total \: time \: taken}$

$or, 70 = 200/ (2 + 100/s) \\ </p><p> or, 70 ×  (2 + 100/s) = 200 \\ </p><p> or, 140 + 7000/s = 200 \\ </p><p> or, 7000/s = 60 \\ </p><p> or, s = \frac{7000}{60} = 116.67 km/h</p><p>$