Math help?

If you start at 1 and skip count by 3s, what is the 100th number in the sequence

Update:

Why do you have to subtract 2?

3 Answers

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  • 2 months ago
    Favorite Answer

    We can set up an arithmetic sequence to describe your number pattern.  I use this general equation to describe the n'th term of such a sequence:

    a(n) = a + b(n - 1)

    where "a" is the first term (1) and "b" is the common difference (3).  Substitute and simplify to get:

    a(n) = 1 + 3(n - 1)

    a(n) = 1 + 3n - 3

    a(n) = 3n - 2

    The 100th term is then:

    a(100) = 3(100) - 2

    a(100) = 300 - 2

    a(100) = 298

  • ?
    Lv 7
    2 months ago

    1, 4, 7, 10, ...

    a_n = 3 n - 2 

    a100 = 298

  • 2 months ago

    3•100 + 1 = 301

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