A person goes from point A to B and comes back. His average speed for the whole journey is 30 km/hr. If his speed while going from A to B is 24 km/hr, then what will be the speed of the person (in km/hr) while coming back from B to A?
A person goes from point A to B and comes back. His average speed for the whole journey is 30 km/hr. If his speed while going from A to B is 24 km/hr, then what will be the speed of the person (in km/hr) while coming back from B to A? Correct Answer 40
We know that,
If ‘x’ km/hr is the speed from A to B and ‘y’ km/hr is the speed from B to A then,
Average speed = 2xy/(x + y)
⇒ 30 = (2 × 24 × y)/(24 + y)
⇒ 15(24 + y) = 24y
⇒ 9y = 24 × 15
⇒ y = 40 km/hr
∴ The speed of the person while coming back from B to A = 40 km/hr
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Feb 20, 2025