Table:
0
A
B
C
D
E
F
G
H
I
J
1
Name
Map colour
First operated
Type
Length
No. Sta
Current Stock
Future Stock
Trips per annum (×1000)
Avg. trips per mile (×1000)
2
Bakerloo line
Brown
1906
Deep Tube
23.2km 14.5 mi
25
1972 Stock
N/A
111136
7665
3
Central line
Red
1900
Deep Tube
74 .0 km 46 .0 mi
49
1992 Stock
N/A
260916
5672
4
Circle line
Yellow
1871
Sub surface
27.2km 17 .0 mi
36
C Stock S Stock
S Stock (Currently replacing C Stock)
114609
4716
5
District line
Green
1868
Sub surface
64 .0 km 40 .0 mi
60
C Stock and D78 Stock
S Stock from 2014
208317
5208
6
Hammersmith & City line
Pink
1864
Sub surface
25.5km 15.9 mi
29
C Stock S Stock
S Stock (Currently replacing C Stock)
114609
4716
7
Jubilee line
Silver
1979
Deep Tube
36.2km 22.5 mi
27
1996 Stock
N/A
213554
9491
8
Metropolitan line
Purple
1863
Sub surface
66.7km 41.5 mi
34
S Stock
N/A
66779
1609
9
Northern line
Black
1890
Deep Tube
58 .0 km 36 .0 mi
50
1995 Stock
N/A
252310
7009
10
Piccadilly line
Dark Blue
1906
Deep Tube
71 .0 km 44.3 mi
53
1973 Stock
N/A
210169
4744
11
Victoria line
Light Blue
1968
Deep Tube
21 .0 km 13.3 mi
16
2009 Stock
N/A
199988
15093
12
Waterloo & City line
Turquoise
1898
Deep Tube
2.5km 1.5 mi
2
1992 Stock
N/A
15892
10595

Questions and formulas:
Question: When 4744 is the avg. trips per mile (x1000) what is the current stock?
Formula: LET(query1,SUMMARIZE(G1,SUMX(J1)),FILTER(query1,CHOOSECOLS(query1,2)=4744))
Formula2: LET(query1,SUMMARIZE(G2:G12,SUMX(J2:J12)),FILTER(query1,CHOOSECOLS(query1,2)=4744))
Level: hard
Question: When green is the map colour what is the future stock?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:J1,B1="Green"),8))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:J12,B2:B12="Green"),8))
Level: medium
Question: When turquoise is the map colour how many avg. trips per mile (×1000)  are there?
Formula: SUMIFS(J1,B1,"Turquoise")
Formula2: SUMIFS(J2:J12,B2:B12,"Turquoise")
Level: easy
Question: When turquoise is the map colour what is the length?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:J1,B1="Turquoise"),5))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:J12,B2:B12="Turquoise"),5))
Level: medium