Q.

Let a1,a2,...,a2024 be an Arithmetic Progression such that a1+(a5+a10+a15+...+a2020)+a2024=2233. Then a1+a2+a3+...+a2024 is equal to __________.          [2025]


Ans.

(11132)

We have,

a1+a5+a10+a15+...+a2020+a2024=2233          ... (i)

Since, a1,a2,...,a2024 be in A.P.

   a1+a2024=a5+a2020=a10+a2015.....

                         {Sum of terms equidistant form ends is equal}

From (i), we get

(a1+a2024)+(a5+a2020)+(a10+a2015)+...=2233

 203(a1+a2024)=2233          [ Total pairs = 203]

 a1+a2024=11

   Sum of n terms in A.P. is

        Sn=n2(a1+a2024)

               =1012×11          [ n = 2024]

   Sn=11132.