A person drives to his office at 40 km/h and reaches 15 minutes late. If he drives at 60 km/h, he reaches 10 minutes early. What is the distance to his office?
Show answer & explanation
Correct answer: A
Explanation
Let the distance to the office be x km.
Traveling at a speed of 40 km/h results in a delay of 15 minutes, whereas traveling at 60 km/h leads to arriving 10 minutes early.
Therefore, the difference between the two times = 15 + 10
= 25 minutes
= 25/60 hours
x/40 - x/60 = 25/60
(3x - 2x)/120 = 25/60
x/120 = 25/60
x = 50 km