What is the heat flow through the ceiling into the attic in 4.5h?

[tquiva]

Homework Statement

The ceiling of a room has an area of 135ft^2. The ceiling is insulated to an R value of 30 (in units of ft^2*deg. F*h/Btu). The surface in the room is maintained at 63 deg. F, and the surface in the attic has a temperature of 38 deg. F. What is the heat flow through the ceiling into the attic in 4.5 h?
Express your answer in (a) BTU and (b) joules.

Homework Equations

The equation I used was the heat current equation with thermal resistance.
H = [A(Th-Tc)] / R

The Attempt at a Solution

The equation I used was the heat current equation with thermal resistance.
H = [A(Th-Tc)] / R
= [(135ft^2)(63 deg. F - 38 deg. F)] / [30 ft^2*deg. F*h/BTU]
= [(135)(25)] / [30]
= 3.8 BTH / h

I've already made an attempt to this problems and my results don't seem to not be right. Can someone please help me?

 

[kuruman]

135*25/30 is not 3.8.