Correct Answer : Both (P1-n*t)*b1*Vf1 & (P2-n*t)*b2*Vf2
Explanation : Discharge of radial flow reaction turbine is product of perimeter of runner, thickness, whirl velocity, at inlet as well as outlet runner vanes. If n blades of thickness t is considered then discharge is (P1-n*t)*b1*Vf1.
Where, P1=perimeter of runner at inlet, P2=perimeter of runner at outlet, b=width, Vf=flow velocity, n=number of blades and t=thickness of blades