Two 4 meter lorry cars are moving along the same direction on a straight road with a constant speeds of 70 km/hr and 90km/hr. if a passenge falls asleep when the faster car is 20m behind the slower car but wakes up after it is 20m ahead of the slower car. find how long he slept?

3 answers

Multiply each speed by .2777 to get them in m/s. You'll car 1 is gaining 5.6 meters each second. For the 40m you're talking about a 7 second nap.

I need the calculation

time = 8.6secs