$A_{1} V_{1}=A_{2} V_{2}$

Where $A_{1}=0.02 \mathrm{m}^{2}$

$V_{1}=2 m / s$

$A_{2}=0.01 \mathrm{m}^{2}$

$\Longrightarrow 0.02 \times 2=0.01 \times V_{2}$

$\Longrightarrow V_{2}=4 m / s$

Now using Bernoulli's theorem

$\frac{P_{1}}{\rho}+\frac{1}{2} V_{1}^{2}=\frac{P_{2}}{\rho}+\frac{1}{2} v_{2}^{2}$

$\Longrightarrow P_{2}=P_{1}+\frac{\rho_{1}}{2}\left[V_{1}^{2}-V_{1}^{2}\right]$

$\Longrightarrow P_{2}=4 \times 10^{10}+\frac{1000}{2}\left[2^{2}-4^{2}\right]-4 \times 10^{10}=3.4 \times 10^{4} N / m^{2}$