Marie has a small copy of rene magritte's famous painting, the schoolmaster. her copy has dimensions 2 inches by 1.5 inches. the scale of the copy is 1 in.: 40cm.
a. find the dimensions of the original painting.
b. find the area of the original painting.
c. since 1 inch is 2.54 centimeters, find the dimensions of the original painting in inches.
d. find the area of the original painting in square inches.

A scale of 1:40 can be read as "one cm on the model corresponds to 40 cm in the original object". or 

"one inch on the model corresponds to 40 inches
this means that  the 2 inches correspond to 2 times 40, that is 80 inches and 1.5 corresponds to 1.5*40=60 inches

which means that the original painting has dimensions of 80 by 60 inches.
b) Area = 80 cm * 60 cm = 4,800 cm²
c) 80 cm * 1 inch / 2.54 cm = 31.50 inches ; 
    60 cm * 1 inch/2.54 cm = 23.60 inches
d) Area = 31.50 in * 23.60 in = 743.40 inches²