Alessandra pose la question : 2. Alan and Brian are two runners. Alan runs at 6.6 m/s and Brian runs at 8.4 m/s. They start from
the same place on a circular 400 m track and run in opposite directions round and round the
track.
(a) How far has Brian run when they pass each other for the first time?
(b) After they pass each other for the second time, how much further does Brian need to run
in order to complete two laps (800 m)? Penny Nom lui répond.
Zoe pose la question : Amy and Joey are situated on a circular track 400 feet around.
Joey starts running at a rate of 10 feet per second.
Amy waits for a full minute, then starts running from the same point (in the same direction) at 12 feet per second.
How many seconds elapse before Amy passes Joey on the track? Penny Nom lui répond.
liz pose la question : a biathlete travels 20 miles in 2.25 hours. She cycles part of the way at 12 mph and runs the rest at 5 mph. How far did she run? Penny Nom lui répond.
Eugene Chan pose la question : A man is running through a train tunnel. When he is 2/3 of the way through, he hears a train that is approaching the tunnel from behind him at a speed of 60 mph. Whether he runs ahead or back, he will reach an end of the tunnel at the same time the train reaches that end. At what rate, in miles per hour, is he running? (Assume he runs at a constant rate.)
I think the answer (12 mph) is wrong. Also, I believe it should read 1/3 of the way through, but don't know how to prove it. Could you come up with some way to prove it, please? I would really appreciate it.
Penny Nom lui répond.
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Centrale des maths reçoit une aide financière de l’Université de Regina et de The Pacific Institute for the Mathematical Sciences.
