The molecular formula of amine is C4H11N. Then ratio of 10, 20 and 30 isomeric amines possible are (structural isomers only)
4 : 3 : 2
4 : 3 : 1
3 : 4 : 1
3 : 3 : 1
30 amine: CH3 - CH2 - N(CH3)2