Question 866195
That's not really an algebra problem. 
I'm assuming pressure is in Pa.
I assume it's 1D incompressible Bernoulli flow.
{{{p[1]+(1/2)*rho*V[1]^2+rho*g*z[1]=p[2]+(1/2)*rho*V[2]^2+rho*g*z[2]}}}
From conservation of mass,
{{{A[1]*V[1]=A[2]*V[2]}}}
{{{V[2]=5(4/8)=2.5}}}{{{m/s}}}
.
.
{{{150000+(1/2)*1000*5^2+1000*9.8*10=p[2]+(1/2)*1000*2.5^2}}}
{{{p[2]=257375}}}{{{Pa}}}