When a person covers the distance between his house and

When a person covers the distance between his house and office at 50 km per hr. he is late by 20 minutes. But when he travels at 60 km per hr. he reaches 10 minutes early. What is the distance between his office and his house?

Let time taken to reach office at 50 kmph be x hrs
Then time taken to reach office

at 60 kmph =		x +	30		hrs
			60

As, distance covered is same,

∴ x × 50 = 60		x +	30
			60

50x = 60x + 30
⇒ x = 3 hrs
Hence, distance = 3 × 50
= 150 km