Find the sum of the series 1 + 4 + 7 +-..to 40terms

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Find the sum of the series 1 + 4 + 7 +……to 40terms

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Amaya 2 weeks 2021-09-06T06:42:55+00:00 1 Answer 0 views 0

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    2021-09-06T06:44:51+00:00

    Answer:

    a= 1 , d= 3 and n = 40

    s(n) = n  \div  2(2a + (n - 1)d)

     = 40 \div 2(2 \times 1  + (40 - 1)3)

     = 20(2 + 39 \times 3)

     = 20 \times 119

     = 2380

    i hope u will understand

    mark me as brainliest…..

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