The distance between town P and town Q is 180km. A drives at an average speed of 60km/h from town P to town Q while B drives from town Q to town P at an average speed of 48km/h. Assuming that they start their journey at 8am, when do they meet each other?
Average speed = Distance travelled / Time
Let the distance travelled by A = D, then we have:
Distance travelled by B = 180 - D. But we have:
D/60 = (180 - D)/48, solve for D
D = 100 km - distance travelled by A
180 - 100 =80 km - distance travelled by B
100/60 =1 2/3 hours, or they will meet after 1 hour and 40 minutes, or at 9:40 am
+128460
Note that Distance / Rate = Time
Since they travel the same time......let the distance that A drives = D
And let the distance that B drives = 180 - D
So....equating times [ in hours ], we have that
D / 60 = [ 180 - D ] / 48 cross-multiply
48D = 60 [ 180 - D ] simplify
48D = 10800 - 60D add 60D to both sides
108D = 10800 divide both sides by 108
100 = D ....so ...the time they meet = [D / 60 ] hrs. = [ 100/ 60 ] hrs. = [5/3] hrs =
[5/3] * 60 minutes = 100 minutes after 8AM = 9:40 AM
