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Math Help - 3 down , 7 to go? :( Please. i don't understand any of this!

  1. #1
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    3 down , 7 to go? :( Please. i don't understand any of this!

    2. Tub A contains 12% apple cider.
    Tub B contains 55% apple cider.
    How many ounces of cider from each tub
    must be gotten to make a 64 ounce drink that
    is 20% apple cider?






    3. Mary is running to school. She leaves home at
    7:00 AM trotting at a speed of 12 mph.
    Her little lamb leaves home at 7:15 AM
    running after her at a speed of 17 mph.
    What time of day will the lamb catch Mary?
    Round your answer to the nearest minute.
    (Example: 10:27 AM)









    4. Granny needs 3 gallons of 15% vinegar for
    her pickles. Bud went to the store and bought
    2 gallons of 50% vinegar. Granny asks:
    How much pure spring water must I mix with
    some of that 50% stuff to get my canner
    filled with 3 gallons of 15% solution?







    5. Use the formulae:

    Given: distance =16t^2 for a falling object,
    And the fact that distance=1100 *t, where the speed of sound is 1100ft/sec in air.
    If you drop a rock into a deep dark well and note that it takes 7 seconds to hear a splash after you drop the rock, how deep is the well? Hint: it takes some time for the rock to fall and then the remainder of the time for sound to travel back up the well for you to hear the splash. You will need the Quadratic formula to solve this one.




    7. Calculate the Medical Dosage.
    Given that a saline medicine bottle contains 5 milligrams
    of Tylenol for each 9 ml of saline
    solution in which it is dissolved.
    Grandma Wilson, who weighs 188 pounds needs
    25 milligrams of Tylenol per 50 kilograms of body
    weight for an I.V. How many ml of saline must she be administered?
    Note: 1kilogram=2.2pounds







    8. I have a collection of nickels, dimes, and quarters
    in a money bag worth $7.95. If the number of
    quarters is one more than the number of nickels
    and the number of dimes is five more than the number
    of nickels, find the number of each type of coin.
    # Nickels ________
    # Dimes_________
    # Quarters________








    9. Freezing weather is coming!
    The radiator in my 450 John Deere track loader
    is full with 18 quarts of fluid that is 15% antifreeze.
    Question: How much must I drain out into a disposable container,
    Then retighten drain plug, and pour back 100% pure
    antifreeze into radiator to make 18 quarts of 40%
    antifreeze.
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  2. #2
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    First up: number 2.

    The system of equations you should set up is this:

    Let x represent ounces of cider from tub A
    Let y represent ounces of cider from tub B

    x + y = 64
    .12x + .55y = .20(64)

    Does this make sense?
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  3. #3
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    uh...

    kinda.

    i see where you set up the formula, ( thank u by the way )
    but then would i juss mult the equation ?
    is it 12.8 oz. ? idk im kinda confused..
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  4. #4
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    Quote Originally Posted by Sweetie View Post
    kinda.

    i see where you set up the formula, ( thank u by the way )
    but then would i juss mult the equation ?
    is it 12.8 oz. ? idk im kinda confused..
    You'd either have to use substitution or elimination techniques to solve the equations simultaneously.
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  5. #5
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    I would use substitution.

    x + y = 64
    .12x + .55y = .20(64)

    From the first equation, y = 64 - x.
    So you can substitute that for y in the second equation:

    .12x + .55(64 - x) = .20(64)

    This equation is linear in x, so you should have no problem simplifying and solving for x, and then using the first equation to get y.
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    Is this right?

    I totally get what you are saying there, it is 11.91 oz ?
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  7. #7
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    Quote Originally Posted by Sweetie View Post
    I totally get what you are saying there, it is 11.91 oz ?
    You should have two answers: one for x (ounces from A) and one for y (ounces from B). I just calculated the approximate answers to be x = 52 and y = 12.
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    oh ok..

    y=11.91
    x=52.09 are those right?
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    OH

    oh i didnt see the rest of your post.. lol thank u so much... could you help me on like on more... if you cant that is perfectly fine.. u have done so much already!
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  10. #10
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    Quote Originally Posted by Sweetie View Post
    y=11.91
    x=52.09 are those right?
    Yes they are. On to the next question...

    Distance equals rate x time.

    At the time Mary and the lamb meet, they will have traveled the same distance, so t_Mr_M = t_Lr_L (M for Mary and L for lamb).
    But t_L = t_M - \frac{1}{4}. (keeping t in terms of hours)

    So we have t_M \times 12 = \left(t_M - \frac{1}{4}\right) \times 17.

    Can you solve that?
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    when i substitute t for time of hours, like what # would i get then to represent hours. 7 hours for mary then 7 hours and 15 min for lamb...???... like im confused cause when i sub. mary's time with 7 i got 84=114.75
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  12. #12
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    Quote Originally Posted by Sweetie View Post
    when i substitute t for time of hours, like what # would i get then to represent hours. 7 hours for mary then 7 hours and 15 min for lamb...???... like im confused cause when i sub. mary's time with 7 i got 84=114.75
    You need to solve the equation for t_M. t_M represents the time elapsed since 7:00 AM. Then you add that time to 7:00 AM to find out what the actual time is.
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  13. #13
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    but what would be Tm ? 7? that would be 14, so it would be 7:14 ? ok now im a lil confused... im sorry Im like horrible at this..

    I swear you are like my only hope for this test.... I'm pitiful
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  14. #14
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    Did you try solving the equation? I got t_M = \frac{17}{20} = \frac{51}{60}, so the time should be 7:51 AM.
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    yea thats right, how in the world did you get 17/20? where did that come from, i was confused on how you come up with a umber for mary's time..... so like Tm was like the variable? but in that eq.. how could you solve that with 2 variables?
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