Solution
We track two linked tables.
Table A lists the six cities with their Pollution Measure (PM) and the state each belongs to.
Table B lists the three states with the PM of their non-urban region (NUR) and their Pollution Index (PI).
| City | PM | State |
|---|---|---|
| Blusterburg | ||
| Noodleton | ||
| Splutterville | ||
| Quackford | ||
| Mumpypore | ||
| Zingaloo |
| State | NUR PM | PI |
|---|---|---|
| Whimshire | ||
| Fogglia | ||
| Humbleset |
There are entities ( cities NURs) sharing distinct PMs:
.
The six cities take six of these values; the three NURs take the remaining three.
The given PM order of the cities is
.
Each PI is
.
Goal: find every PM, every state assignment, and the three PIs.
| City | PM | State |
|---|---|---|
| Blusterburg | 30 | |
| Noodleton | 50 | |
| Splutterville | 60 | |
| Quackford | 70 | |
| Mumpypore | 80 | |
| Zingaloo | 90 |
| State | NUR PM | PI |
|---|---|---|
| Whimshire | ||
| Fogglia | ||
| Humbleset |
All six city PMs are filled from the single NURcity rule.
Let the cities in increasing order be and the NURs be .
The number of (NUR, city) pairs with NUR city equals, for each NUR, the count of cities below it, summed up. This total must be .
If two or more NURs were above the smallest city , the total would be .
If no NUR were above , the total would be .
So exactly one NUR lies above , and it must lie below (otherwise it would exceed cities).
The ordering of all nine values is therefore forced:
.
Mapping to :
.
So the cities are
,
and the three NUR PMs are .
| City | PM | State |
|---|---|---|
| Blusterburg | 30 | Humbleset |
| Noodleton | 50 | |
| Splutterville | 60 | |
| Quackford | 70 | |
| Mumpypore | 80 | |
| Zingaloo | 90 |
| State | NUR PM | PI |
|---|---|---|
| Whimshire | ||
| Fogglia | ||
| Humbleset | 40 |
Blusterburg is assigned to Humbleset, and Humbleset's NUR PM is set to .
The only pair with NUR city is over , i.e. over Blusterburg.
This NUR and this city both belong to Humbleset.
So Humbleset's NUR PM , and Blusterburg () is one of Humbleset's two cities.
The remaining NUR PMs belong to Whimshire and Fogglia, in some order.
| City | PM | State |
|---|---|---|
| Blusterburg | 30 | Humbleset |
| Noodleton | 50 | |
| Splutterville | 60 | W/F |
| Quackford | 70 | |
| Mumpypore | 80 | W/F |
| Zingaloo | 90 |
| State | NUR PM | PI |
|---|---|---|
| Whimshire | ||
| Fogglia | ||
| Humbleset | 40 |
Splutterville and Mumpypore are pinned to the same state, which is either Whimshire or Fogglia (marked W/F).
Since is an integer for every , a PI is an integer only when
is an integer,
i.e. the two city PMs of a state sum to a multiple of .
City PMs modulo :
, and .
A pair sums to a multiple of only if both are or both are .
Only and are , so they must be paired together.
Thus one state's cities are Splutterville () and Mumpypore ().
Humbleset already contains (which is ), so this is not Humbleset.
Hence Splutterville and Mumpypore share Whimshire or Fogglia, and Humbleset's second city is one of .
| City | PM | State |
|---|---|---|
| Blusterburg | 30 | Humbleset |
| Noodleton | 50 | |
| Splutterville | 60 | W/F |
| Quackford | 70 | |
| Mumpypore | 80 | W/F |
| Zingaloo | 90 | Humbleset |
| State | NUR PM | PI |
|---|---|---|
| Whimshire | ||
| Fogglia | ||
| Humbleset | 40 | 50 |
Zingaloo is fixed as Humbleset's second city, giving Humbleset PI .
Let Humbleset with :
,
giving for .
The state has PI .
Humbleset must have the strictly highest PI.
If : , but the state can reach , so Humbleset is not highest. Reject.
If : ; the leftover cities form (sum ) and (sum ), both giving . With NURs one of these states becomes , tying Humbleset. Reject.
So : Humbleset Blusterburg, Zingaloo, with
.
| City | PM | State |
|---|---|---|
| Blusterburg | 30 | Humbleset |
| Noodleton | 50 | Fogglia |
| Splutterville | 60 | Whimshire |
| Quackford | 70 | Fogglia |
| Mumpypore | 80 | Whimshire |
| Zingaloo | 90 | Humbleset |
| State | NUR PM | PI |
|---|---|---|
| Whimshire | 20 | 45 |
| Fogglia | 10 | 35 |
| Humbleset | 40 | 50 |
Whimshire and Fogglia are completed.
The four remaining cities split as (Splutterville, Mumpypore) and (Noodleton, Quackford), with NURs .
.
.
The combination and gives equal PIs, which is rejected (PIs must be distinct).
So takes NUR (PI ) and takes NUR (PI ).
Fogglia has the lowest PI, so Fogglia : Noodleton (), Quackford (), NUR , PI .
Whimshire : Splutterville (), Mumpypore (), NUR , PI .
| City | PM | State |
|---|---|---|
| Blusterburg | 30 | Humbleset |
| Noodleton | 50 | Fogglia |
| Splutterville | 60 | Whimshire |
| Quackford | 70 | Fogglia |
| Mumpypore | 80 | Whimshire |
| Zingaloo | 90 | Humbleset |
| State | NUR PM | PI |
|---|---|---|
| Whimshire | 20 | 45 |
| Fogglia | 10 | 35 |
| Humbleset | 40 | 50 |
Every PM, state and PI is now uniquely determined.
Verification of the constraints:
The only NUR city pair is (Humbleset's NUR over Blusterburg) — exactly one such pair, and both lie in Humbleset.
PIs are (Humbleset), (Whimshire), (Fogglia) — distinct integers, with Humbleset highest and Fogglia lowest.
All nine entities (six cities and three NURs) have a known PM and a known state.
Fogglia (the lowest PI) holds Noodleton () and Quackford () with NUR .
.
Answer: .