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Math Help - Grade 8 Algebra

  1. #1
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    Grade 8 Algebra



    I have these Algebra Problems that I just do not understand. So far I understand the whole idea of what algebra is and variables, but I do not understand these problems.

    http://i52.tinypic.com/2md3xjo.jpg

    http://i53.tinypic.com/245zu6p.jpg

    Your help would be greatly appreciated.

    Thanks~!
    Last edited by JesseElFantasma; April 12th 2011 at 07:55 AM.
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  2. #2
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    taking the cooking time example:

    "15 minutes + 35 minutes per kilogram"

    This would be
    for 1kg: t = 15 + (35*1)
    for 2kg: t = 15 + (35*2)
    for 3kg: t = 15 + (35*3)
    for 4kg: t = 15 + (35*3)
    ...
    for 10kg: t = 15 + (35*10)
    ...

    What if i told you the number of kilograms was "x" insead of specifying the number
    for xkg: t = 15 + (35*x)


    The same approach may help on the other question
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  3. #3
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    Quote Originally Posted by SpringFan25 View Post
    taking the cooking time example:

    "15 minutes + 35 minutes per kilogram"

    This would be
    for 1kg: t = 15 + (35*1)
    for 2kg: t = 15 + (35*2)
    for 3kg: t = 15 + (35*3)
    for 4kg: t = 15 + (35*3)
    ...
    for 10kg: t = 15 + (35*10)
    ...

    What if i told you the number of kilograms was "x" insead of specifying the number
    for xkg: t = 15 + (35*x)


    The same approach may help on the other question
    Thanks!

    So if the variable for kg was m I would have to go : m kg: t= 15+ (35x2)
    That would mean that the amount of kilo's is two. Right?
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  4. #4
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    The first one asks you to fill out a table showing how much remains to be paid off you are told they are 1000- 200, 1000- 200(2), 1000- 200(3), etc. What are those amounts? After the week 1 he still owes 1000- 200(1), after week 2 he still owes 1000- 200(2), after week 3 he still owes 1000- 200(3), after week 4 he still owes 1000- 2(4), etc. How much does he still owe after week n? Do you see where the "week number" fit into each of those? Replace that with n.

    The second gives a recipe that says you must roast for 35 minutes for each kilogram plus an additional 15 minutes. If your roast weighed 2 kg, you roast it for 35 minutes for each kg: 2(35)= 70 minutes, then and additional 15 minutes: 70+ 15= 85 minutes. Suppose your roast weight 3 kg. How long would you cook it? What if it were four kg.? Think about what you did there. What if it were "x" kg.?
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  5. #5
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    Thanks!

    So if the variable for kg was m I would have to go : m kg: t= 15+ (35x2)
    That would mean that the amount of kilo's is two. Right?
    yes, the formula for 2kg would be
    t=15 + (35*2)

    the formula for m kilos would be
    t = 15 + (35*m)
    Last edited by SpringFan25; April 12th 2011 at 07:55 AM. Reason: added quote to clarify what im responding to
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  6. #6
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    Quote Originally Posted by HallsofIvy View Post
    The first one asks you to fill out a table showing how much remains to be paid off you are told they are 1000- 200, 1000- 200(2), 1000- 200(3), etc. What are those amounts? After the week 1 he still owes 1000- 200(1), after week 2 he still owes 1000- 200(2), after week 3 he still owes 1000- 200(3), after week 4 he still owes 1000- 2(4), etc. How much does he still owe after week n? Do you see where the "week number" fit into each of those? Replace that with n.

    The second gives a recipe that says you must roast for 35 minutes for each kilogram plus an additional 15 minutes. If your roast weighed 2 kg, you roast it for 35 minutes for each kg: 2(35)= 70 minutes, then and additional 15 minutes: 70+ 15= 85 minutes. Suppose your roast weight 3 kg. How long would you cook it? What if it were four kg.? Think about what you did there. What if it were "x" kg.?
    Thank you halls of Ivy.
    I understand the second explanation, but I do not understand the 1st.
    Must I go for month 4 : 80 000- (20 000 x t)

    If so, what is that (A) for?

    THANKS!
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  7. #7
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    Quote Originally Posted by JesseElFantasma View Post
    Thank you halls of Ivy.
    I understand the second explanation, but I do not understand the 1st.
    Must I go for month 4 : 80 000- (20 000 x t)

    If so, what is that (A) for?

    THANKS!
    What (A) I dont see any A,and i dont see the numbers used by HoI either and I dont see any 20,000 so am a bit confused

    original loan 80,000
    repayment is 2,000 per month so at end of
    month 1 its 80,000 - 2000= 78,000
    Month 2 its 80,000 - 2,000 - 2,000 or 80,000 - (2,000 * 2)

    Month n its 80,000 - (2,000*n)
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  8. #8
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    Quote Originally Posted by Carlow52 View Post
    What (A) I dont see any A,and i dont see the numbers used by HoI either and I dont see any 20,000 so am a bit confused

    original loan 80,000
    repayment is 2,000 per month so at end of
    month 1 its 80,000 - 2000= 78,000
    Month 2 its 80,000 - 2,000 - 2,000 or 80,000 - (2,000 * 2)

    Month n its 80,000 - (2,000*n)
    Thank you
    And about the (A)

    In the description it says: relating the amount that he still owes (A) after any number of months (t)
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  9. #9
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    Grand, the old mince pies are not the Mae West so I missed the A and t in the .jpg No reply needed
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