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Thread: Math Homework Help

  1. #1
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    Question Math Homework Help

    - Four more than two thirds of a number is 22. Find the number.
    - Find three consecration odd integers whose sum is 105
    - A 100L tank now contains 240L of water. How long will it take to fill the tank using a pump that pumps 25L per minutes.

    Any help??
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  2. #2
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    Quote Originally Posted by inulled View Post
    - Four more than two thirds of a number is 22. Find the number.

    Solve $\displaystyle \frac{2}{3}x+4 = 22$


    Quote Originally Posted by inulled View Post
    - Find three consecration odd integers whose sum is 105
    Do you mean consecutive?

    If so solve

    $\displaystyle (2x+1)+(2x+3)+(2x+5)=105$
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  3. #3
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    Quote Originally Posted by inulled View Post
    - Four more than two thirds of a number is 22. Find the number.
    - Find three consecration odd integers whose sum is 105
    - A 100L tank now contains 240L of water. How long will it take to fill the tank using a pump that pumps 25L per minutes.

    Any help??
    1. Let x be the number you wish to find:

    $\displaystyle \dfrac{2}{3}x + 4 = 22$.

    2. Let k be an integer. Since 2k is always even our first odd number is

    $\displaystyle 2k-1$ hence the next two odd numbers are $\displaystyle 2k+1$ and $\displaystyle 2k+3$

    Hence $\displaystyle 2k-1 + 2k+1 + 2k+3 = 105$ (you can simplify here)

    3. The tank would already be overflowing, is there a typo in the question?
    Last edited by e^(i*pi); Sep 30th 2010 at 02:04 PM. Reason: white space
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  4. #4
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    yeah
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  5. #5
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    Quote Originally Posted by e^(i*pi) View Post
    1. Let x be the number you wish to find: $\displaystyle \dfrac{2}{3}x + 4 = 22$. Solve for x

    2. Let k be an integer. Since 2k is always even our first odd number is $\displaystyle 2k-1$ hence the next two odd numbers are $\displaystyle 2k+1$ and $\displaystyle 2k+3$
    Hence $\displaystyle 2k-1 + 2k+1 + 2k+3 = 105$ (you can simplify here)

    3. The tank would already be overflowing, is there a typo in the question?
    im not too sure. this is a friend of mines homework... so i would say use your best judgment
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  6. #6
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    Quote Originally Posted by inulled View Post
    - Four more than two thirds of a number is 22. Find the number.
    - Find three consecration odd integers whose sum is 105
    - A 100L tank now contains 240L of water. How long will it take to fill the tank using a pump that pumps 25L per minutes.

    Any help??
    You can word them as follows....

    $\displaystyle \frac{2}{3}x+4=22$

    Then to find the number x, you need to remove the 4 and the 2/3 from the left hand side.

    Hence, first subtract 4 from both sides, then multiply both sides by 3/2.


    For the second one, only a certain 3 digits, increasing by 2, sum to 105.
    It happens they are odd.

    $\displaystyle x+(x+2)+(x+4)=105$

    Add these up

    $\displaystyle x+x+x+2+4=105$

    $\displaystyle 3x+6=105\Rightarrow\ 3x=105-6$

    divide by 3 for the answer.


    Has the tank been replaced by a bigger one?

    the idea is... it takes 1 minute to get 25L into the tank.
    therefore it takes 2 minutes to get (2)25L=50L into it,
    it takes 3 minutes to get (3)25=75L into it etc

    EDIT: We are supposed to be helping you, so it defeats the purpose to give solutions for a third party.
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  7. #7
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    thanks man
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  8. #8
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    Quote Originally Posted by inulled View Post
    - Find three consecration odd integers whose sum is 105
    let x = second odd integer

    (x-2) + x + (x+2) = 105

    solve for x, then determine (x-2) and (x+2)
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