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…so how far is that tree on the end?

please help with math on this hard problem?

A laser range finder is able to compute a distance up to 3 km with an accuracy of 99.5%. What possible error is there in a reported measurement of 2500 meters?
A less than 5 meters
B between 5 an 10 meters
C between 10 and 15 meters
D over 20 meters

3km=3000 meters
3000*.005(the error rate)=15

15/3000 compared to X/2500

15*2500=37500
3000*X=3000X

37500=3000X

37500/3000=3000X/3000
12.5=X
So C is your answer.

  1. sep_n Said,

    Possible error = relative error * reported measurement
    Possible error = 0.5% * 2500 m
    Possible error = 12.5 m

    Therefore, C is the correct answer
    References :

  2. thrust_reversal Said,

    the answer is c
    References :

  3. arif Said,

    the error in length measured is 12.5m.

    thus the correct answer is c (between 10 and 15 m).
    References :

  4. gregory_dittman Said,

    3km=3000 meters
    3000*.005(the error rate)=15

    15/3000 compared to X/2500

    15*2500=37500
    3000*X=3000X

    37500=3000X

    37500/3000=3000X/3000
    12.5=X
    So C is your answer.
    References :

  5. yupchagee Said,

    2500m*.005=12.5m
    C. between 10 & 15 m
    References :

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