Pump Effeciency in Affinity Law

[Mahil]

Using the pump affinity law, why does the given pump efficiency disregarded on the calculation of head#2?

 

[Solid]

The question doesn't make any use of efficiency. No change in diameter, no change in density and it is a static column it is pumping against.

 

[Solid]

The question doesn't make any use of efficiency. No change in diameter, no change in density and it is a static column it is pumping against.