Find the sum of the sequence 45+46+47+48+- +124

Question

Find the sum of the sequence 45+46+47+48+…. +124

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Gabriella 1 week 2021-10-14T00:28:12+00:00 1 Answer 0

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    2021-10-14T00:29:24+00:00

    Answer:

    \boxed{6760}

    Step-by-step explanation:

    The formula for the first n terms of an arithmetic sequence is

    Sₙ = n(a₁+ aₙ)/2

    1. Find the number of terms

    n = (124 – 45) + 1 = 79 + 1 = 80

    2. Find the sum

     a₁ =   45

    a₈₀ = 124

    S_{80} = 80 \left(\dfrac{45 + 124 }{2}\right) = 80 \times 84.5= \boxed{\mathbf{6760}}

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