Answer:
a=10 and c=20
Explanation:
This is a system of equations. I will solve using the substitution method.
a+c=30
12a+8c=280
Solving for a:
a+c-c=30-c
a=30-c
Substituting a into the second equation:
12(30-c)+8c=280
360-12c+8c=280
360-4c=280
-4c=-80
c=20
Substituting into the original equation:
a+20=30
a+20-20=30-20
a=10
To prove this answer is correct, I will plug the solutions back in to the original equation.
a+c=30
10+20=30
30=30, True
12a+8c=280
12*10+8*20=280
120+160=280
280=280, True
Therefore, a=10 and c=20.