Answer:
24 Degrees
Step-by-step explanation:
Supplementary Angles are two angles with a sum of 180 degrees.
x+6+7x+30=180
8x+36=180
8x=144
18=x
Plug in 18 to angle A
18+6=24
24 degrees
5% p.a will rate of interest
your answer would be c) 9