Correct Answer - Option 4 : 18 km
Given
A teacher driving his vehicle at 24 kmph, reaches her school 5 minutes late. If she had driven the vehicle 25% faster on an average she would have reached 4 minutes earlier than the scheduled time.
Concept used
When the distance is the speed is inversely proportional to time
Calculaton
The initial speed of the teacher is 24 km/hr
Final speed = 24× 125/100
⇒ 30 km/hr
⇒ The ratio of speed = 24 : 30
⇒ 4 : 5
⇒ Time ratio = 5 : 4
According to question
⇒ Time gap = 9 minute
⇒ 1 unit = 9 minutes
⇒ 5 unit = 45 minute or 3/4 hour
⇒Distance = 24 × 3/4
⇒ 18 km
∴ Her school distance is 18 km
