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seanspan
Feb 18, 2010, 04:30 PM
Two towns are 20km apart. A biker leaves from the first town at 20km/h and another biker leaves the second town at the same time travelling 15km/h. Where and when will they meet?

Im confused on how to set up and solve this question some help would be appreciated

ebaines
Feb 19, 2010, 07:47 AM
If you consider town A to be at position x = 0, and town B to be at x = 20 Km, then the position of the first biker as a function of time is:

x1 = 20 Km/hr * t

The position of the second biker is:

x2 = 20 Km - 15 Km/hr * t

Note that the velocity of that second biker is negative - that's because he is going in the direction opposite to the direction of the first biker.

Set X1 = x2 and solve for t.

Unknown008
Feb 19, 2010, 11:48 AM
OP: Please, refrain from posting your questions twice.

https://www.askmehelpdesk.com/math-sciences/kinematics-two-bikers-leaving-same-time-where-do-they-meet-when-448778.html

ebaines
Feb 19, 2010, 11:53 AM
Thinking some more about this problem - both Unknown008 and I assumed that the two bikers are riding toward each other. This may not be right - the second biker could actually be riding way from the first. If this is so, then the 15 km/hr term needs a positive sign, not negative.

Unknown008
Feb 19, 2010, 12:06 PM
Hmm, I get your point. No information concerning direction was said. So, there might be technically much more solutions, infinite even...

However, since most problems like that often come like the two moving bodies go towards each other...

seanspan
Feb 19, 2010, 02:11 PM
Thank you that helped
And they were travelling towards each other I forgot to mention that