The sum of 5 and 9th term of an AP is 72 and the sum of 7 and 17 term is 97. Find the AP.​

Question

The sum of 5 and 9th term of an AP is 72 and the sum of 7 and 17
term is 97. Find the AP.​

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Clara 1 month 2021-08-13T02:22:42+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-08-13T02:23:43+00:00

    Answer:

    let AP = a, a+d , a+2d ,a+3d ,….

    so 5th term = a+4d

    and 9th term = a+8d

    according to question

    a+4d +a+8d = 72

    2a + 12 d = 72 (eqs 1)

    similarly a+6d + a +16 d=97

    2a + 22d= 97 (eqs 2)

    substracting eqs 1 by 2

    it becomes -10d = -25

    so ,d = 5/2

    putting value of d in eqs 1

    a = 21

    so AP = 21, 23.5 ,26 , 28.5 ……..

    0
    2021-08-13T02:24:40+00:00

    Answer:

    here first number is 21 and difference between them is 5/2

    Step-by-step explanation:

    a+(n-1)d

    as we know that ,.

    a+4d+a+8d=72 ——–(1)

    a+6d+a+16d=97———-(2)

    now subtract (1)eq from (2)eq

    u will get d=5/2

    and by getting d now we can find a

    so, 2a+12d=72

    2a+(12*5/2)=72

    2a+30=72

    2a=42

    a=21

    I hope it will help u

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