A student performed the experiment of determination of focal length of a concave mirror by $u-v$ method using an optical bench of $1.5\mathrm{m}$. The focal length of the mirror used is $24\mathrm{cm}$. The maximum error in the location of the image can be $0.2\mathrm{cm}$. The five sets of $\left(u,v\right)$ values recorded by the student in (cm) are $\left(42,56\right), \left(48,48\right), \left(60,40\right), \left(66,33\right), \left(78,39\right)$. The data set(s) that cannot come from experiments and is (are) incorrectly recorded, is(are)