Question

A train travels from City X to City Y at a speed of 44 kmph, while on its return journey the train was travelling at speed of 77 kmph. Find the average speed of the train.

Answer 1

Answer:

Let, distance 308 Km(LCM of,44 and 77)

time for onwardjourney=308/44=

= 7 hrs

time for return journey=308/77

= 4 hrs

Av.speed=Total dist./Total time

= 616/ 11=56 km/hr. Ans

Answer 2

AnswEr :

Le the Distance Betwⁿ City X and Y be s.

⋆ Total Distance Travelled

» s + s

» 2s

Let the Speed₁ be 44 km/h and, Speed₂ be 77km/h

⋆ Total Time Taken

» Distance /Speed₁ + Distance /Speed₂

» s /44 + s /77

» (7s + 4s) /308

» 11s /308

• Formula to Calculate Average Speed is :

⇒ Total Distance / Total Time Taken

⇒ 2s / (11s /308)

⇒ 2s /11s × 308

⇒ 2 × 28

⇒ 56 km/h

჻ Average Speed of the Train is 56 km/h

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• Shortcut Trick to Solve this :

⇒ A.S. = ( 2 × S₁ × S₂ ) / ( S₁ + S₂ )

• Plugging the Values

⇒ A.S. = (2 × 44 × 77) / (44 + 77)

⇒ A.S. = (2 × 44 × 77) / 121

⇒ A.S. = (2 × 4 × 7)

⇒ A.S. = 56 km/h