Time and Distance

To solve this problem, you can use the formula "distance = speed * time" to find the time it takes for the car to travel 100 meters at a speed of 36 km/hr.

First, you need to convert the speed from km/hr to m/s. You can do this by multiplying the speed by 1000 and dividing by 3600. This gives us: 36 km/hr = 36 * 1000 / 3600 = 10 m/s.

Next, you can plug the values into the formula to find the time it takes for the car to travel 100 meters: time = 100 m / 10 m/s = 10 seconds.

Distance = speed * time

To convert the speed from km/hr to m/s, we use the conversion factor: 1 km/hr = 5/18 m/s

Speed in m/s = 20 km/hr * (5/18 m/s/km/hr) = 50/9 m/s
Time = 2 minutes = 2 * 60 seconds = 120 seconds

Distance = speed * time = (50/9 m/s) * 120 seconds = 6000/9 meters = 666.6666666666667 meters.

The length of the bridge is 666.6666666666667 meters

Given that the distance traveled is 8 kilometers and the relative speed of the two boys is 2 km/hr, 

we can use the time formula to calculate the time taken:

Time = distance/speed = 8 km / 2 km/hr = 4 hours.