N owes PW of ₹ 3146 due 3/2 yr hence
i.e. {3146 x 100} / {100 + (14 x 3/2)} = (3146 x 100) / (100 + 21)
= 314600 / 121
= ₹ 2600
N owes PW of ₹ 2889 due 6 months hence
i.e. {2889 x 100}/{100 + (14 x 1/2)} = (2889 x 100)/(100 + 7)
= (2889 x 100)/107 = ₹ 2700
∴ N must pay ₹ (2700 - 2600) i.e. ₹ 100 to M.