$$\angle A, \angle B, \angle C$$ are three angles of a triangle. If  $$\angle A - \angle B$$ = $$15^\circ$$, $$\angle B - \angle C$$ = $$30^\circ$$, then $$\angle A$$, $$\angle B$$ and $$\angle C$$ are 

Given  $$\angle A-\angle B = 15^\circ \rightarrow (1)$$
       $$\angle B-\angle C = 30^\circ\rightarrow (2)$$
       From equation (1), $$\angle B = \angle A-15^\circ$$
       Substituting $$\angle B$$ value in equation (2)
        $$(\angle A-15)-\angle C = 30^\circ$$
       $$\Rightarrow \angle C = \angle A-45^\circ$$
        We know that $$\angle A+\angle B+\angle C=180^\circ$$
        Substituting $$\angle A,\angle B,\angle C$$ values in above equation
        $$\angle A+(\angle A-15^\circ)+(\angle A-45^\circ)=180^\circ$$
        $$\Rightarrow 3\angle A=240^\circ$$
        $$\angle A=80^\circ$$
        Substituting $$\angle A$$ value in equation (1)
        $$80^\circ-\angle B=15^\circ$$
        $$\Rightarrow \angle B=65^\circ$$
        Substituting $$\angle B$$ in equation (2)
        $$65^\circ-\angle C = 30^\circ$$
        $$\Rightarrow \angle C = 35^\circ$$
        $$\therefore \angle A=80^\circ, \angle B=65^\circ, \angle C=35^\circ$$