Answer :

bennygene
C=4         because 4/6 is equivalent to 6/9 and they would reduce down to 2/3
[tex]\frac { 6 }{ 9 } =\frac { c }{ 6 } \\ \\ \frac { 2 }{ 3 } =\frac { c }{ 6 } \\ \\ 6\cdot \frac { 2 }{ 3 } =\frac { c }{ 6 } \cdot 6[/tex]

[tex]\\ \\ c=\frac { 12 }{ 3 } \\ \\ \therefore \quad c=4[/tex]