Pressure of blood in an artery

[axer]

Homework Statement

1. The average pressure of the blood in a person’s arteries is 100 mmHg. What is the average pressure in an artery in the head of standing person 40 cm above the heart? (blood density= 1.05x103 kg/m3,Mercury density = 13.6x103 kg/m3 and g=10 m/s2)

Homework Equations

The Attempt at a Solution

it is clear that I have to include both 100 mmHg and the h= 0.4m to find Pressure at head artery.

pressure heart=pressure head + pgh <-- hight of head
100x10^-3 x 10 x 13600= pressure head + (1059x10x0.4)
pressure head= 3.2. this is wrong because the answer written is 9.09 x 103 N/m2.
Nevermind <-- wrong calculations I divided instead of subtracting (don't know how to delete this post)

 

[Merlin3189]

Your method sounds ok.
But it seems to me that,
100x10^-3 x 10 x 13600= pressure head + (1059x10x0.4)
∴ 13600 = Ph + 4236
∴ Ph = 13600 - 4236 = 9364

Not what you want, but not what you got