Answer:
C = 27/40 or 0.675
Explanation:
1/8 + c = 4/5 opposite sign -
1/8 - 4/5 now multiply to make the same denominator
1/8 multiply 5 to both top and bottom = 5/40
4/5 multiply 8 to both bottom and top = 32/40
now subtract with the same denominator
32/40 - 5/40 = 27/40 now simplify
27/40 simplifies too 0.675