Posted by Tammy on Tuesday, March 15, 2011 at 2:40am.
Two cyclists depart from the same point. One travels due East at 18km/hr while the other travels NorthWest at 20km/hr. How long will it be before they are 80km apart?

Maths  bobpursley, Tuesday, March 15, 2011 at 9:06am
80^2=t^2(20^2+18^2)
solve for time t. 
Maths  Tammy, Tuesday, March 15, 2011 at 9:31am
Wonderful, thank you

Maths  Anonymous, Friday, October 28, 2016 at 1:32am
Two cyclists leave a park and ride in opposite directions, one averaging 5 mph and the other 10 mph. If they have twoway radios with a 10mile range, for how many minutes will they remain in radio contact?