Table:
0
A
B
C
D
E
F
G
H
I
J
1
county id
name
population
police officers
residents per officer
case burden
crime rate
police force
location
county public safety
2
1
Abbotsford
128165
187
685
81
118.0
Abbotsford Police Department
East
3
2
Burnaby
204320
253
808
100
123.0
RCMP
East
4
3
Campbell River
30810
40
770
137
178.0
RCMP
West
5
4
Castlegar
7821
11
711
107
150.0
RCMP
North
6
5
Central Saanich
16821
21
801
39
49.0
Central Saanich Police
East
7
6
Chilliwack
73066
91
803
140
174.0
RCMP
West

Questions and formulas:
Question: How many counties for each police force?
Formula: SUMMARIZE(H1,SUMX(A1))
Formula2: SUMMARIZE(H2:H7,SUMX(A2:A7))
Level: easy
Question: the number of counties of each police force.
Formula: SUMMARIZE(H1,SUMX(A1))
Formula2: SUMMARIZE(H2:H7,SUMX(A2:A7))
Level: easy
Question: Which location has the most counties?
Formula: TAKE(SORT(SUMMARIZE(I1,SUMX(A1)), 2, -1), 1)
Formula2: TAKE(SORT(SUMMARIZE(I2:I7,SUMX(A2:A7)), 2, -1), 1)
Level: hard
Question: The location with the most counties.
Formula: TAKE(SORT(SUMMARIZE(I1,SUMX(A1)), 2, -1), 1)
Formula2: TAKE(SORT(SUMMARIZE(I2:I7,SUMX(A2:A7)), 2, -1), 1)
Level: hard
Question: the name and id of the most crowded country.
Formula: TAKE(SORT(SUMMARIZE(HSTACK(B1,A1),SUMX(C1)), 3, -1), 1)
Formula2: TAKE(SORT(SUMMARIZE(HSTACK(B2:B7,A2:A7),SUMX(C2:C7)), 3, -1), 1)
Level: hard
Question: Name of the most populous county.
Formula: LET(a,HSTACK(B1,A1),b,A1,c,CHOOSECOLS(TAKE(SORT(SUMMARIZE(A1,SUMX(C1)), 2, -1), 1),1),UNIQUE(FILTER(a,NOT(ISNA(XLOOKUP(b,c,c))))))
Formula2: LET(a,HSTACK(B2:B7,A2:A7),b,A2:A7,c,CHOOSECOLS(TAKE(SORT(SUMMARIZE(A2:A7,SUMX(C2:C7)), 2, -1), 1),1),UNIQUE(FILTER(a,NOT(ISNA(XLOOKUP(b,c,c))))))
Level: hard
Question: total number of counties.
Formula: SUM(A1)
Formula2: SUM(A2:A7)
Level: easy
Question: Country ids and police forces for all locations apart from the east 
Formula: LET(query1,FILTER(A1:J1,I1<>"east"),UNIQUE(CHOOSECOLS(query1,8,1)))
Formula2: LET(query1,FILTER(A2:J7,I2:I7<>"east"),UNIQUE(CHOOSECOLS(query1,8,1)))
Level: hard
Question: all police forces and county ids except those in the east
Formula: LET(query1,FILTER(A1:J1,I1<>"east"),UNIQUE(CHOOSECOLS(query1,8,1)))
Formula2: LET(query1,FILTER(A2:J7,I2:I7<>"east"),UNIQUE(CHOOSECOLS(query1,8,1)))
Level: hard
Question: the number of counties.
Formula: SUM(A1)
Formula2: SUM(A2:A7)
Level: easy
Question: Country ids and polices force of non-eastern locations
Formula: LET(query1,FILTER(A1:J1,I1<>"east"),UNIQUE(CHOOSECOLS(query1,8,1)))
Formula2: LET(query1,FILTER(A2:J7,I2:I7<>"east"),UNIQUE(CHOOSECOLS(query1,8,1)))
Level: hard
Question: the police forces and ids of counties which don't locate in the east.
Formula: LET(query1,FILTER(A1:J1,I1<>"east"),UNIQUE(CHOOSECOLS(query1,8,1)))
Formula2: LET(query1,FILTER(A2:J7,I2:I7<>"east"),UNIQUE(CHOOSECOLS(query1,8,1)))
Level: hard