Answer: a) Density of,
New York = 420
Maryland = 619
Pennsylvanian = 286
b) The required order from most dense state to least dense state is,
Maryland, New York, Pennsylvanian
Step-by-step explanation:
a) Since, 
Here, The population of New York = 19,795791
Area = 47126
Thus, the Density of the New York
= 
Similarly, Density of Maryland,
= 
And, Density of Pennsylvania
= 
b) Since, 619 > 420 > 286
Thus, the states in the decreasing order of their density,
Maryland, New York, Pennsylvanian