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        riddles >> easy >> Olympic Puzzle
        
(Message started by: rloginunix on Aug 14^th, 2016, 11:45am)

Title: Olympic Puzzle
Post by rloginunix on Aug 14^th, 2016, 11:45am

At the peak of 2016' Games in Rio ...

A and B are 75 'straight-line' kilometers apart. As a bicycle rider takes off from B and rides toward A at a constant speed of 15 kilometers per hour (km/h), a runner takes off from A and runs toward B at a constant speed of 10 km/h.

As the runner takes off from a start line, a fly takes off from the runner's shoulder and flies at a constant speed of 20 km/h toward the bike rider. After the fly touches down on the bike rider's shoulder, she instantly turns around and flies toward the runner. After the fly touches down on the runner's shoulder, she instantly turns around and flies toward the bike rider. And so on the fly flies back and forth - until the runner and the bike rider meet.

In total, how much distance did the fly cover by the time the runner and the bike rider met?

Title: Re: Olympic Puzzle
Post by towr on Aug 14^th, 2016, 12:55pm

[hide]75/(15+10)*20=60

That's a mighty fast fly (thrice the usual top speed for a housefly), and a very slow cyclist (under a third the top speed of a tour cyclist).
[/hide]

Title: Re: Olympic Puzzle
Post by rloginunix on Aug 16^th, 2016, 7:41am

Correct. And fast.

[hide]Not only she is fast - she is a tough little bugger - managed to keep her head straight after an infinite number of turns ...[/hide]