The units are the complete story on this question. All of the choices are over 1 so the units make the answer over one. It takes more feet than it does inches to make the scale. The correct units are 120 feet / 3 inches. That makes A and B both incorrect.
You can't get 360 by any method but multiplication. The units for multiplication would be ft*in. So D is wrong. That only leaves you with C which is the answer.
400 pages in 5 days but 120 on the first day so 400-120=280 280 is what he read in the 4 days following so divide 280 equally among the 4 days You get 70 per day after the first
