Math Question?

A boat traveling with the current, can go 30 miles in 2 hr. The return journey upstream takes 1 hr longer. Find the speed of the boat in still water and find the speed of the current.

4 Answers

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  • 1 decade ago
    Favorite Answer

    Let b = speed of boat in still water,

    and c = speed of current.

    On the downstream journey, the boat's total speed is b + c.

    On the upstream journey, the boat's total speed is b - c.

    Using the formula, Distance = Speed * Time,

    the downstream formula is : 30 = (b + c) * 2,

    while the upstream formula is : 30 = (b - c) * 3

    From the 1st formula, we get : b + c = 30 / 2 = 15 mph

    From the 2nd formula, we get : b - c = 30 / 3 = 10 mph

    Adding the equations gives : 2b = 25, so b = 12.5 mph.

    Subtracting the 2nd from the 1st gives : 2c = 5, so c = 2.5 mph.

  • Anonymous
    1 decade ago

    20

  • 1 decade ago

    15 mph downstream

    10 mph upstream

    (10 + 15)/2 = 12.5 mph

  • Anonymous
    1 decade ago

    well you know i dont know maths soo .blahh.. =]

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