Absolute pressure at the bottom of a container

[kimlu]

Homework Statement

A container is filled to a depth of 20.0 cm with water. On top of the water floats a 29.0-cm-thick layer of oil with specific gravity 0.800. What is the absolute pressure at the bottom of the container?
(Answer in Pa)

Homework Equations

P= ρgh+ P(atmospheric)

The Attempt at a Solution

(800)(9.81)(29-20)+101.3x10^3= 171932

Webassign says "Your response differs from the correct answer by more than 10%. Double check your calculations."

Did I substitute something wrong?

 

[Tanya Sharma]

Hi kimlu...

You have to calculate pressure at the bottom of the container ,not between the interface of water and oil .

You also seem to have forgotton to convert 'cm' to 'm' .

 

[ehild]

Homework Statement

A container is filled to a depth of 20.0 cm with water. On top of the water floats a 29.0-cm-thick layer of oil with specific gravity 0.800. What is the absolute pressure at the bottom of the container?
(Answer in Pa)

Homework Equations

P= ρgh+ P(atmospheric)

The Attempt at a Solution

(800)(9.81)(29-20)+101.3x10^3= 171932

Webassign says "Your response differs from the correct answer by more than 10%. Double check your calculations."

Did I substitute something wrong?

Yes.

Why did you subtract the thickness of water from the thickness of oil?

ehild