we know that
scale factor=measure in the model/measure in the actual
measure in the model=6 1/2 in----> (6*2+1)/2---> 13/2 in
measure in the actual=975 ft
scale factor=(13/2)/975----> 13/(975*2)---> 13/1950
scale factor= 13/1950---> divide by 13----> 1 in/ 150 ft
the answer is
1 in/ 150 ft