a maths puzzle...

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A person traveled from Meridell to Brightvale, 50 miles away, with his pet parrot. When he arrived in Brightvale, he let the parrot fly free while he traveled back to Meridell, at a speed of 10 miles per hour. The parrot, who flies at 25 miles per hour, arrived at Meridell and promptly turned around until he got to the person. Once he got to the person, he turned around and returned to Meridell. He continued to fly back and forth between the person and Meridell until the parrot reached Meridell.

How many miles total did the parrot travel on this trip?

i got this from neopets, i changed some words to make it less confusing.

could you also expain how to do it, if you can work out how to do it, i got stuck near the end.

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They key is total travel time.

The person walks 50 miles @ 10 miles/hour. That is 5 hours.

The bird flies 25 mph for 5 hours = 125 miles.

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im trying to figure out the EXACT same thingy buddy (see *Confused*)

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but you must add the 50 miles the bird travalled with the person.

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Ah, yes. Thank you, grasshopper.

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WRONG
it's funny cause you'll all wrong. it says that the bird flies BETWEEN the PERSON and the CITY. THE POSITION OF THE PERSON CHANGES EVERY HOUR, THEREFORE... the distance that the bird flies is NOT always 25 miles per hour... this makes ALL of your answers on all the posts of this wrong Sad

for u guys. The only thing im debating about is the fact of using miles in decimals. You would use decimals because once the bird is on it's first way back to the person, the bird would be moving faster, making the person not walk the full 10 miles before the bird heads back.

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Re: WRONG
drewdad got it when he got corrected.

omgwtflol wrote:

the distance that the bird flies is NOT always 25 miles per hour...

remember that distance is not velocity.

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Re: WRONG

omgwtflol wrote:

it's funny cause you'll all wrong. it says that the bird flies BETWEEN the PERSON and the CITY. THE POSITION OF THE PERSON CHANGES EVERY HOUR, THEREFORE... the distance that the bird flies is NOT always 25 miles per hour... this makes ALL of your answers on all the posts of this wrong for u guys. The only thing im debating about is the fact of using miles in decimals. You would use decimals because once the bird is on it's first way back to the person, the bird would be moving faster, making the person not walk the full 10 miles before the bird heads back.

Riddles of this type are quite common. I'm certain of my answer. If you dispute it, can you offer an alternate answer? With explanation?

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Re: WRONG

omgwtflol wrote:

it's funny cause you'll all wrong. it says that the bird flies BETWEEN the PERSON and the CITY. THE POSITION OF THE PERSON CHANGES EVERY HOUR, THEREFORE... the distance that the bird flies is NOT always 25 miles per hour... this makes ALL of your answers on all the posts of this wrong for u guys. The only thing im debating about is the fact of using miles in decimals. You would use decimals because once the bird is on it's first way back to the person, the bird would be moving faster, making the person not walk the full 10 miles before the bird heads back.

The fact that the bird flies between the person and the city has been accounted for. Nobody said each leg of the bird's flight is a constant distance. However, the bird's speed is constant. Given that the bird flies for 5 hours at 25 mph, it must fly 125 miles. If you wish to calculate the length of each leg (using decimals), go ahead. However, it's not necessary, and if you do it correctly, you'll arrive at the same answer.

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Oh, what the hell. Here are the distances traveled for each round trip the bird makes. Although this series is infinite, after 23 terms it converges to the answer to six decimal places. The first round trip is 71 3/7 miles. Each trip is 3/7 the length of the previous trip. Therefore, the total distance the bird flies is 71 3/7 * SUM(n=0 to infinity, (3/7)^n). The infinite sum is a geometric series that sums to 7/4 (sum = 1/(1-r), r = 3/7). 71 3/7 * 7/4 = 125.

Code:

Remaining   Distance Man    Distance Bird

Distance    Walks Before    Flies From Man

For Man     Bird Returns    To City To Man

---------   ------------    --------------

50.000000     28.571429     71.428571

21.428571     12.244898     30.612245

 9.183673      5.247813     13.119534

 3.935860      2.249063      5.622657

 1.686797      0.963884      2.409710

 0.722913      0.413093      1.032733

 0.309820      0.177040      0.442600

 0.132780      0.075874      0.189686

 0.056906      0.032518      0.081294

 0.024388      0.013936      0.034840

 0.010452      0.005973      0.014932

 0.004479      0.002560      0.006399

 0.001920      0.001097      0.002743

 0.000823      0.000470      0.001175

 0.000353      0.000201      0.000504

 0.000151      0.000086      0.000216

 0.000065      0.000037      0.000093

 0.000028      0.000016      0.000040

 0.000012      0.000007      0.000017

 0.000005      0.000003      0.000007

 0.000002      0.000001      0.000003

 0.000001      0.000001      0.000001

 0.000000      0.000000      0.000001

              ---------    ----------

Total         50.000000    125.000000

a maths puzzle...

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