Question

Find ques no 69 and ans is 625 please give ans fast...

Answer 1

3, 9/2, 6, 15/2,........upto 25th term.


here
a=3,

d=9/2 - 3=3/2=1.5,

n=25,

therefore sum upto 25th terms=25/2 [2×3+(25-1)×1.5],

=25/2×[6+24×1.5],

=25/2×[6+36],

=25/2 × 42,

=25×21,

=525