Typo, or did I miss the math?

[Scuba_Jenny]

I am taking an online class, and here it is on a Sunday night when I got to this part:

ATA vs. PSI

To express Absolute pressures in psi instead of ATA, we must convert using our known constant of 1ATA = 14.7 psi.
To convert Absolute Pressure (ATA) to psi, simply multiply by 14.7 as in the example below:
2 ATA x 14.7 psi/ATA = 29.4 psi
To express Hydrostatic pressures alone in psi instead of ATA, we must convert using our known constants of 0.445 psi/fsw and 0.432 psi/ffw.
For example:
At 66fsw the hydrostatic pressure is: 2atm = 33fsw x 0.445 psi/fsw = 29.36 psi
At 68ffw the hydrostatic pressure is: 2atm = 34ffw x 0.432 psi/ffw = 29.36 psi

My question. In Bold, should that be 66fsw? If not. Why? Please explain.

 

[Wookie]

I am taking an online class, and here it is on a Sunday night when I got to this part:



My question. In Bold, should that be 66fsw? If not. Why? Please explain.

You are correct to be confused.

At 66 FSW, the hydrostatic pressure (water pressure) is 2 atm. The absolute pressure is 3 atm. I don’t understand the point that the text is trying to make.

 

[tursiops]

I am taking an online class, and here it is on a Sunday night when I got to this part:



My question. In Bold, should that be 66fsw? If not. Why? Please explain.

Yes, it should be written as:
At 66fsw the hydrostatic pressure is: 2atm x 33fsw/atm x 0.445 psi/fsw = 29.36 psi
At 68ffw the hydrostatic pressure is: 2atm x 34ffw/atm x 0.432 psi/ffw = 29.36 psi

 

[inquis]

My question. In Bold, should that be 66fsw?

Yes, the bolded should be 66 fsw, otherwise the equal sign would be incorrect.

I also think this bit of text is fairly useless, since nearly everyone using imperial units will use atm for depth-related pressures.

 

[dmaziuk]

You are correct to be confused.

At 66 FSW, the hydrostatic pressure (water pressure) is 2 atm. The absolute pressure is 3 atm. I don’t understand the point that the text is trying to make.

It's just explaining interconversion between different silly units. It has nothing to do with actual depths, which makes it even more silly.