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?

Guest Aug 5, 2017

#1**0 **

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

Guest Aug 5, 2017

#2**+1 **

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

CPhill
Aug 5, 2017