Answer:
27
Step-by-step explanation:
643-166=477
477÷18=26.5
Then, round to the nearest whole.
Which makes it 27 sets.
Set up a system of equations:
B=2+3C
B+C=90
The variable B is already solved, so plug into bottom equation:
2+3C+C=90
2+4C=90
4C=88
C=22
Plug C back in:
B+22=90
B=68
So B is 68 degrees and C is 22 degrees
Hope this helped!