A boy covers a certain distance between his house and school on a cycle. Riding on an average speed of 15 km/h, he is late by 10 min. However, with an average speed of 20 km/h, he reaches the school 5 min earlier. Find the distance between his house and school.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3. i.e. 15 km.
Given that
Riding on an average speed of 15 km/h, he is late by 10 min
Riding an average speed of 20 km/h, he reaches the school 5 min earlier
Let the distance between his house and school be D
Formula used
Distance = Speed × Time
According to the question
⇒ D/15 - 10/60 = D/20 + 5/60
⇒ D/15 - D/20 = (5 +10)/60
⇒ D(4 - 3)/60 = 5/60
⇒ D = 15 km