Question

When Happy travelled at 12 km/hr. he arrived at his office 5 minutes late. If he increased his speed by 8 km/hr. he arrived 5 minutes early, find the value of distance. 
1. 5 km
2. 3 km
3. 4 km
4. 6 km

Answer 1

Correct Answer - Option 1 : 5 km

Given:

Speed = 12 km/hr

Increased speed = 8 km/hr

Formula used:

Time = Distance/ Speed

Calculation:

Let the distance be x km

According to the question

[(x/12) – (5/60)] = [(x/20) + (5/60)]

⇒ (5x – 5)/60 = (3x + 5)/60

⇒ (5x – 5) = (3x + 5)

⇒ (5x – 3x) = 5 + 5

⇒ 2x = 10 

⇒ x = 5

∴ The value of distance is 5 km.