Let the first term a and the common ratio r of a geometric progression be positive integers. If the sum of…

Let the first term a and the common ratio r of a geometric progression be positive integers. If the sum of squares of its first three terms is 33033, then the sum of these three terms is equal to
  1. 241
  2. 231
  3. 210
  4. 220

Solution

Given that,

a2+ar2+ar22=33033, a,rN

a21+r2+r4=112×273

On comparing both sides of the equation we get,

a=11 and 1+r2+r4=273

r2+r4=272

r21+r2=16×17

r=4

Now a+ar+ar2=11+11×4+11×16

=11+44+176=231.

Therefore, the required value is 231

Asked in: JEE Main 2023 (10 Apr Shift 1)

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