I drive a distance of 200km around the city and my car’s average speed is 25 km/h. How far do I then need to drive at an average speed of 100 km/h to raise my car’s average speed for the whole time to 40 km/h?
+128407 The original time is D / R = 200/25 = 8 hrs
So.....he Total Distance is given by 200 + 100T
Where T is the additional time driving at 100 km / hr
So Total Distance / Total Time = 40
[200 + 100T ]
___________ = 40 cross-multiply
8 + T
200 + 100T = 40 [ 8 + T] simplify
200 + 100T = 320 + 40T
60T = 120 divide both sides by 60
T =120 /60 = 2 additional hrs of driving at 100 km.hr = (2) 100 = 200 additional km
