When a person goes to his office from his house with a speed of 10 km/hr, he is late by 20 minutes. When he goes with speed of 15 km/hr, he is late by 5 minutes. What is the distance (in km) between his office and house?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 7.5
Time = Distance/Speed
Let the distance between office and house be x.
According to question,
(x/10) - (x/15) = (20 + 5)/60
⇒ (3x - 2x)/30 = 25/60
x = 15/2 , or 7.5 km