We know that scale factor=1 in/7.5 ft scale factor=measurements on the blueprint/measurements <span> in the actual </span>measurements on the blueprint=[measurements in the actual*scale factor] so
for 18 ft measurements on the blueprint=[18 ft*(1 in/7.5 ft)-----> 2.4 in
for 16 ft measurements on the blueprint=[16 ft*(1 in/7.5 ft)-----> 2.1 in
the dimensions on the blueprint are 2.4 in x 2.1 in