Question

A man completes a journey in 5 hours. He completes the first half of the journey at a speed of 20 km/hr and the second half at a speed of 25 km/hr What is the total journey in
?
5 km
O 6 km
O None of these
5.4 km
are walking at 6 km/hr and 8​

Answer 1

Answer:

1/2*x/20 + 1/2*x/25 = 5

x/20 + x/25 = 10

9x/100 = 10

x = 1000/9 = 111.11 km

Answer 2

A man completes a journey in 5 hours. He completes the first half of the journey at a speed of 20 km/hr and the second half at a speed of 25 km/hr.

We have to find the length of total journey.

Let x be the length of total journey.

Step 1 : The man traveled half of the journey at a speed of 20 km/hr.

∴ time taken to travel half journey , t₁ = distance/speed = (x/2)/20 = (x/40) hrs

Step 2 : The man traveled half of the journey at a speed of 25 km/hr.

∴ time taken to travel half journey, t₂ = distance/speed = (x/2)/25 = (x/50) hrs

Step 3 : total time taken to complete the journey is 5 hrs.

∴ t₁ + t₂ = 5

⇒x/40 + x/50 = 5

⇒9x/200 = 5

⇒x = 1000/9 = 111.1 km

Therefore the length of the journey is 111.1 km.