Question

A train covers the first 60 kilometre of its journey at a speed of 80 kilometre per hour, the next 90 km at a speed of 100 km per hour and the rest of its it's 330 kilometre journey at a speed of 120 kilometre per hour. Find the total time taken to complete its journey .Also find its average speed.​

Answer 1

Answer :

• Total time taken to complete its journey = 4.4 hours
• Average speed = 109.09 km/h

Given :

• A train covers the first 60km of its journey at a speed of 80km per hour. The next 90km at speed of 100km per hour and the rest of its 330 km journey at a speed of 120 km per hour

To find :

• Total time taken
• Average speed

Solution :

To find the total time taken to complete its journey we must to use the distance time formula and to find the Average speed we must use the formula of average speed

According to question,

Time taken would be

• 60/80 hours

• 90/100 hours

• 120/330 hours

We know that,

• Time = Distance/Speed

Let the time be T₁ ,T₂ ,T₃

➞ T₁ = 60/80 = 0.75 hours

➞ T₂ = 90/100 = 0.9 hours

➞ T₃ = 330/120 = 2. 75 hours

Finding the total time taken to complete its journey :

• Total time taken to complete its journey = T₁ + T₂ + T₃

➞ 0.75 + 0.9 + 2.75

➞ 4.4 hours

Hence , Total time taken to complete its journey = 4.4 hours

Finding the average speed :

We know that,

• Average speed = Total distance covered/Total time taken

➞ 60 + 90 + 330 / 4.4

➞ 480/4.4

➞ 109.09 km/h

Hence ,Average speed = 109.09 km/h