Question

1/3 + 1/15 + 1/35 + 1/63 + ................ 1/575 + 1/675

Answer 1

1/1x3 + 1/3x5 + 1/5x7 + 1/7x9 +... + 1/23x25 + 1/25x27 = 

1/2 x (2/1x3 + 2/3x5 + 2/5x7 +..... 2/23x25 +2/25x27 = 

1/2 x (1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 +...... + 1/23 - 1/25 + 1/25 - 1/27 = 

1/2 x (1 - 1/27) =

1/2 x 26/27 = 13/27

Answer 2

13/27