Here, cross-section of the tube, $a_{1}=8.0\,\mathrm{cm}^{2}=8.0\times10^{-4}\,\mathrm{m}^{2}$ The speed of liquid in the tube, $v_{1}=1.5\,\mathrm{m}\,\mathrm{min}^{-1}=\frac{1.5}{60}\,\mathrm{m}\,\mathrm{s}^{-1}$$=0.025\,\mathrm{m}\,\mathrm{s}^{-1}$diameter of a hole, $D=1.0\,\mathrm{mm}=10^{-3}\,\mathrm{m}$Therefore, cross-section of a hole, $\frac{\pi D^{2}}{4}=\frac{\pi}{4}\times(10^{-3})^{2}$$=\frac{\pi}{4}\times10^{-6}\,\mathrm{m}^{2}$Therefore, total cross-section of 40 holes, $a_{2}=\frac{\pi}{4}\times10^{-6}\times40\,\mathrm{m}^{2}$If $v_2$ is the speed of ejection of the liquid through the holes, then $a_1 v_1 = a_2 v_2$or $v_{2}=\frac{a_{1} v_{1}}{a_{2}}$$=\frac{8.0\times10^{-4}\times0.025}{\frac{\pi}{4}\times10^{-6}\times40}$$=0.637\,\mathrm{m}\,\mathrm{s}^{-1}$.