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 paintong has dimentions of 80 by 60 inches.
