If the mean and variance of five observations are $\frac { 24 } { 5 }$ and $\frac { 194 } { 25 }$ respectively and the mean of first four observations is $\frac { 7 } { 2 }$, then the variance of the first four observations is equal to\\
(1) $\frac { 4 } { 5 }$\\
(2) $\frac { 77 } { 12 }$\\
(3) $\frac { 5 } { 4 }$\\
(4) $\frac { 105 } { 4 }$