Question 39130
Decimal problems like this 
0.15 - 0.24(c - 0.50) = 0.63
usually become easier if you first multiply everything by 100
15 - 24(c - 0.50) = 63
15 - 24c + 12 = 63
27 - 24c = 63
-24c = 36
c = -3/2