Ppump=68600Pa
Step-by-step explanation:
We understand that the sum of the pressures in the tank and the pump is equal to that of the Nozzle,
Ptank+Ppump=Pnozzle
For the pressure we also know that it is given by
P=Pgh
So
Ppump=pg(h2-h1)
Ppump=1000*9.8(27-20)
Ppump=68600Pa