Answer:
A=80 , B=65, C=35
Explanation:
A-B=15 ⇒A=B+15
B-C=30⇒-C=30-B ⇒C=B-30
the sum of angle of a triangle = 180
A+B+C=180 ( substitute A and C)
B+15+B+B-30=180
3B-15=180
3B=180+15
B=195/3=65
C=B-30 ⇒ C=65-30=35
A=B+15=65+15=80
check : A+B+C=180
80+65+35=180 ( correct)