n small drops of same size are charged to V volts each. If they coalesce to form a signal large drop, then its potential will be?

Let potential f 1 drop = Kq/r =V 

Volume of n drops = volume of bigger drop 

n  4/3 pi (r)^3  = 4/3 pi (R)^3

Therefore ,  R = ( (n)^1/3) r 

also charge remains conserved 

charge on 1 drop = q 

charge on big drop containing n drops = (nq) 

Therefore potential on big drop = K (nq)/ ((n)^1/3)r

=(( n)^2/3) Kq/r

= (( n)^2/3) V

Thank you sooo much!!!