Kajol riding his bike at 24 km/h reaches his office 5 minutes late. If he would have reached the office 4 minutes earlier than the scheduled time by traveling 25% faster, how far is his office from his house in kms?

Question: Kajol riding his bike at 24 km/h reaches his office 5 minutes late. If he travels 25% faster, he reaches 4 minutes earlier than the scheduled time. How far is his office from his house?

Solution:
Speed 1 = 24 km/h
Speed 2 = 24 + 25% of 24 = 30 km/h

Let distance = d km
Time at 24 km/h = d/24
Time at 30 km/h = d/30

Difference in time = 5 + 4 = 9 minutes = 9/60 hours

According to the question,
d/24 - d/30 = 9/60
⇒ (5d - 4d)/120 = 9/60
⇒ d/120 = 9/60
⇒ d = 18
∴ Distance = 18 km

Correct Answer: ঘ) 18