Observe the values of a, b, c given in the table. If we choose numbers a, b and c from rows a, b and c respectively, what is the maximum possible value of c - b / a? a | 2 | 4 | 6 | 8 | 10 -- | -- | --- | --- | --- | ----- b | 3 | 5 | 7 | 9 | 11 c | 5 | 10 | 15 | 20 | 25
