Question

Every 10 minutes one motor car starts from A towards B. The distance between A and B is 60 km. The speed of the motor car is 60 km/hr. The number of cars met by a passenger riding in a car which starts from B to A simultaneously with one of the motor cars from A will be (The car in which the passenger is also travels at 60 km/hr)

Answer 1

Dear Student,

The passenger will travel the distance A - B in one hour.The distance between two adjacent motor car is 10 km, because their speed is 60 km/h and they starts every 10 minutes.

As 60 km/h = 1 km/min,
=> Approach speed of the passenger and the motor car is 2 km/min.
So the time in which passenger will meet a motor car each
$Time=\frac{dis\tan ce}{speed}$
The distance between two adjacent motor car is 10 km(written above)
Approach speed of the passenger and the motor car is 2 km/min(written above)
=> 10 /2
=> 5 minutes

On Travelling 60 km distance starting from the 0 minute passenger(1st one) will meet 13 motor cars meeting them each 5 minutes.

Regards