Math, asked by harshadmorajkar, 16 hours ago

the sum of three consecutive term of an AP is 9 and the sum of their square is 35 find the sum of all numbers between 200 and 400 which are divisible by 7​

Answers

Answered by Breh7
0

Answer:

Step-by-step explanation:

The numbers lying between 200 and 400 which are divisible by 7 are 203,210,217,...399

∴ The first term,  a=203

Last term, a  n =399 & Common difference, d=7

Let the number of terms of the A.P. be n.

∴a  n

399=a+(n−1)d

⇒399=203+(n−1)7

⇒7(n−1)=196

⇒n−1=28⇒n=29

∴S  29  =  2 29 /2 (203+399)

​ 602)=(29)(301)=8729

Thus, the required sum is 8729

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