can someone help me with this question??
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First number which when divided by 4 yields 1 as remainder is 13. [13/4 = 1].
Last number which when divided by 4 yields 1 as remainder 1 is 97.[97/4 = 1]
Hence, the AP is 13,17,21,25,...97
Now,
First term a = 13.
Common difference d = 17 - 13 = 4
Last term an = 97.
We know that an = a + (n - 1) * d
= > 97 = 13 + (n - 1) * 4
= > 97 - 13 = 4n - 4
= > 84 = 4n - 4
= > 88 = 4n
= > n = 22.
Now,
Sum of n terms of an AP sn = (n/2)[a + l]
⇒ 22/2[13 + 97]
⇒ 11[110]
⇒ 1210.
Therefore, the answer is 1210 - Option(B).
Hope this helps!
khushikanungo2pdxcn7:
thank you soo much
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