$a v _{1}=\frac{ a }{2} v _{2}$

$v _{2}=2 v _{1}$

From Bernoulli's theorem,

$P _{1}+\rho g h_{1}+\frac{1}{2} \rho v _{1}^{2}= P _{2}+\rho g h_{2}+\frac{1}{2} \rho v _{2}^{2}$

$P _{1}- P _{2}=\rho\left[\left(\frac{ v _{2}^{2}- v _{1}^{2}}{2}\right)+ g \left( h _{2}- h _{1}\right)\right]$

$4100=800\left[\left(\frac{4 v _{1}^{2}- v _{1}^{2}}{2}\right)+10 \times(0-1)\right]$

$\frac{41}{8}+10=\frac{3 v _{1}^{2}}{2}$

$\frac{121}{8} \times \frac{2}{3}= v _{1}^{2}$

$v _{1}=\sqrt{\frac{ I 21}{4 \times 3} \times \frac{3}{3}}$

$v _{1}=\frac{\sqrt{363}}{6} \; m / s$

$X =363$