There are two parts to this question that we should consider seperately:
Firstly, we need to work out the total thrust force that is being applied through the seat onto the astronaut. Critically, this is the sum of both his weight and the force required to produce the resultant 47ms^-2 acceleration rather that just one of these.thrust = 76 x (47 + 9.81) = 4,318N
To determine the pressure, we can use the relevant equation: Pressure = Force / Area because we know both what the total force through the seat and the area of the seat are.Pressure = 4,318 / 0.095 = 45,400 Pa to 3 significant figures