• Q. First term is of arithmatic progression sequence is 79 and the difference between consecutive numbers is 13 , Find the sum numbers from 44 to 48 terms.
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  • Term at 44 position is 79 + (44 - 1)x 13

    = [79 + (43)x 13 ]

    = [79 + 559]

    = [638]

    ie. S44 = (638)


  • Then,
    Sum of 44 to 48 position is (5/2)[2*638 + (5 - 1)x 13 ]

    = (2.5)[1276 + (4)x 13]

    = (2.5)[1276 + 52]

    = (2.5)[1328]

    ie. S44 to S48 = (3320)


  • Second method:-

    Term at 44 position is 79 + (44 - 1)x 13
    = 638 (=t1)


  • Term at 45 position is 79 + (45 - 1)x 13
    = 651 (=t2)


  • Term at 46 position is 79 + (46 - 1)x 13
    = 664 (=t3)


  • Term at 47 position is 79 + (47 - 1)x 13
    = 677 (=t4)


  • Term at 48 position is 79 + (48 - 1)x 13
    = 690 (=t5)


  • so the sequance of numbers from position 44 to 48 is 638, 651, 664, 677, 690

    = 638 + 651 + 664 + 677 + 690
    ie. S44 to S48 = 3320

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