Let s 1 , s 2 , s 3 . . . . , s 10 respectively be the sum of 12 terms of 10   A . Ps whose first terms…

Let s1,s2,s3....,s10 respectively be the sum of 12 terms of 10 A.Ps whose first terms are 1, 2, 3,....,10 and the common differences are 1, 3, 5,...,19 respectively. Then i=110si is equal to

  1. 7220
  2. 7360
  3. 7260
  4. 7380

Solution

Given,

First term of A.P are 1,2,3....10, so general term of the first term will be i

And common difference are 1,3,5,...., so general term of common difference is given by 2i-1

Now sum of the A.P  is given by,

Si=1222×i+12-12i-1

Si=62×i+112i-1

Si=144i-66

So, i=110Si=i=110144i-66i=1101

i=110Si=14410×112-66×10

i=110Si=79210-66×10

i=110Si=7260

Hence this is the correct option.

Asked in: JEE Main 2023 (13 Apr Shift 1)

Practice more Sequences and Series questions on Aicharya