Let ABC be a right-angled triangle with BC as the hypotenuse. Lengths of AB and AC are 15 km and 20 km respectively. The minimum possible time, in minutes, required to reach the hypotenuse from A at a speed of 30 km per hour is
Hypotenuse BC of right angled triangle ABC=√(202+152)=25 km.
Perpendicular distance from point A to hypotenuse BC=(20×15)25=12 km
For minimum time, minimum distance should be taken which is perpendicular distance.
Hence, minimum time in minutes =(12×60)30=24