Math, asked by hameedabdul556, 10 months ago

Consider an arithmetic sequence whose common difference is 7 and sum of first 20 terms is 1530. write the algebraic expression of the sequence.

Answers

Answered by peculiari
7

Answer:

the sequence is 10, 17, 24, ............

the 20th term is 143

Step-by-step explanation:

d = 7

S20 = 1530

Sn = n/2 {2a+(n-1)d}

1530 = 20/2 {2a+(19)7}

1530 = 10 {2a+133}

153 = 2a + 133

153 - 133 = 2a

therefore,

a = 20/2

a = 10

let's try it out

S20 = 20/2{2(10)+(19)7}

= 10{20+133}

= 10{153}

= 1530

therefore, the required A.P. is

10,17,24.......

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