See image — AITS & Test Series Chemistry Question

💡 Solution & Explanation

Given 2 ar 8   2 8 a r  Sum,   2 2 8 8 r S 1 r r 1 r     Sum is minimum when  2 3 f r r r   is maximum.  2 f ' r 2r 3r 0     2 r 3  is point of maxima min 8 S 54 4 2 1 9 3          