Find the zeroes of integers between 10 and 500 which are divisible by

1.	Find the zeroes of integers between 10 and 500 which are divisible by 7 ?
Answer» So, the sum of integers between 10 and 500 is 17885. AP are : 14 , 21 , 28 ......497 . So, a= 14 , Tn = 497 , d= 7 . Now, Tn = a + (n-1) d => 497 = 14 +(n-1) 7 => n= 70 . Sn = n/2 ( Tn + a) => Sn = 70/2 ( 497+14) => Sn = 35× 511 => Sn = 17885 .

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