This month's Challenge Question: Specs & Techs from GlobalSpec:
Two cars start moving in opposite directions from point A. They are traveling at constant speeds on a
closed race track. The cars cross for
the first time at point B, then at point C, and a third time at point A. If the
speed of Car 2 is 50 mph, what is the minimum speed of Car 1?
And the answer is:
Because the cars move at a constant speed, the distance from point A to
point B and from point B to point C and from point C to point A must be the
same (you can set three linear equations and solve them to see about this
statement). Because the cars first meet at point B and car 1 has to travel
twice the distance to get to point B, the minimum speed of car 1 must be 100
mph. If car 2 travels at a speed given
by 100n mph, where n are a positive integer, the cars will also meet at point B
for the first time. Therefore to meet at the three given point in the order
specified, the minimum speed of car 2 must 100 mph, or twice the speed of car
1.

Comments rated to be Good Answers:
Comments rated to be "almost" Good Answers: