N is admitted for 20% share, therefore remaining 80% share will be divided among J, K, L and M.
Their new ratio is given as 3 : 4 : 2 : 1, total = 10 parts.
\[
\text{J} = \frac{3}{10} \times 80 = 24,\;
\text{K} = \frac{4}{10} \times 80 = 32,\;
\text{L} = \frac{2}{10} \times 80 = 16,\;
\text{M} = \frac{1}{10} \times 80 = 8,\;
\text{N} = 20
\]
Dividing by 4, the new ratio becomes:
\[
8 : 6 : 4 : 2 : 5
\]