A car leaves Denver at 30 km/h traveling south. Two hours later, another car leaves Denver traveling south at 40 km/ h. How many hours had the first car been traveling when the second car catches up?
3 answers
Please help I am lost on this one and another one i posted
this is another just like the others.
The relative speed of the 2nd car is 10 km/hr faster.
In two hours, the 1st car has gone 60km.
So, it takes 6 hrs for the 2nd car to catch up. By that time, the 1st car has been going for 8 hours.
Or, as Reiny showed you, you want to find where the distances are equal. Since distance = speed * time,
30x = 40(x-2)
30x = 40x - 80
10x = 80
x = 8
The relative speed of the 2nd car is 10 km/hr faster.
In two hours, the 1st car has gone 60km.
So, it takes 6 hrs for the 2nd car to catch up. By that time, the 1st car has been going for 8 hours.
Or, as Reiny showed you, you want to find where the distances are equal. Since distance = speed * time,
30x = 40(x-2)
30x = 40x - 80
10x = 80
x = 8
mofor left home and drove south at an average speed of 21mph. emily left 2 hours later and drove in the same direction but with an average speed of 35mph. find the numbr of hours mofor drove before emily caught up.
1 answer