Correct Answer: 15 km
Explanation:
Let the distance = x
Here, the difference in time
= 20 - 5 = 15 min
= 15/60 = 1/4h
Speed during next journey
= 15 + 5 = 20 km/h
According to the question,
x/15 - x/20 = 1/4
⇒ 4x - 3x/60 = 1/4
⇒ x = 60/4 = 15
∴ x = 15 km
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