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The sum of father's and mother's ages is 84. if the age of father 5 years ago is the same as the age of mother 3 years later, how old is father now?

Answers

  • Réponse publiée par: hajuyanadoy

    answer:

    step-by-step explanation: step 1: find the number of terms

    the nth term of an arithmetic sequence is given by

    t

    n

    =

    a

    +

    (

    n

    1

    )

    d

    . we know

    t

    n

    (-57), r (-5) and a (8), however we don't know n. we will therefore solve for

    n

    .

    57

    =

    8

    +

    (

    n

    1

    )

    5

    57

    =

    8

    5

    n

    +

    5

    57

    13

    =

    5

    n

    70

    =

    5

    n

    n

    =

    14

    the sequence has

    14

    terms.

    step 2: apply the formula for sum:

    when dealing with arithmetic series, we will frequently use two formulas to help us find the sum. they are:

    s

    n

    =

    n

    2

    (

    2

    a

    +

    (

    n

    1

    )

    d

    )

    s

    n

    =

    n

    2

    (

    a

    +

    t

    n

    )

    since we know the first term, the last term and the number of terms, we have enough information to use the latter; this one is more efficient and easy to use than the first.

    s

    n

    =

    n

    2

    (

    a

    +

    t

    n

    )

    s

    14

    =

    14

    2

    (

    8

    +

    (

    57

    )

    )

    s

    14

    =

    7

    (

    8

    57

    )

    s

    14

    =

    343

    hence, the sum of this arithmetic sequence is

    343

    .

    practice exercises:

    determine the sum of the following sequence:

    3

    ,

    14

    ,

    25

    ,

    ,

    179

    hopefully this helps, and good luck!

    dikit dikit mo nalang bawal kasi naka higa eh

  • Réponse publiée par: shannel99
    1. g/f
    2. f*g
    3. fog
    4. f+g
    5. f/g
    6. f-g
  • Réponse publiée par: jemuelpogi
    Interest = 51,200 - 40,000
    =11,200

    time = i/(pr)
    = 11,200/(40,000)(0.12)
    = 11,200 / 4,800
    = 2.33 or 2 years and 4 months
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The sum of father's and mother's ages is 84. if the age of father 5 years ago is the same as the age...