Q.

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            [2023]

1 231   
2 241   
3 210     
4 220  

Ans.

(1)

We have, first term=a 

Common ratio=r 

According to question, a2+(ar)2+(ar2)2=33033 

a2(1+r2+r4)=33033 

a=11,  r=4 

 Required sum =a+ar+ar2 

=11+11×4+11(4)2=11+44+176=231