Table:
0
A
B
C
D
E
1
# Tubes
Converter
Det/Pre-amp
Audio Amp
Rectifier
2
4
X
X
X
X
3
4
X
X
X
(selenium)
4
5 (standard)
X
X
X
X
5
6
X
X
X
X
6
6
X
X
X X (push-pull)
X
7
8
X
X X (push-pull)
X X (push-pull)
X
8
8
X
X
X X (push-pull)
X

Questions and formulas:
Question: Name the rectifier for Det/Pre-amp of x and # tubes of 4
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,(C1="x")*(A1=4)),5))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E8,(C2:C8="x")*(A2:A8=4)),5))
Level: medium
Question: Name the # tubes with Det/Pre-amp of x and audio amp of x x (push-pull)
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,(C1="x")*(D1="x x (push-pull)")),1))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E8,(C2:C8="x")*(D2:D8="x x (push-pull)")),1))
Level: medium
Question: Name the det/pre-amp with # of tubes of 8
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,A1=8),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E8,A2:A8=8),3))
Level: medium
Question: Name the det/pre-amp with # tubes of 4 and rectifier of x
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,(A1=4)*(E1="x")),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E8,(A2:A8=4)*(E2:E8="x")),3))
Level: medium
Question: Name the # tubes with audio amp of x
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,D1="x"),1))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E8,D2:D8="x"),1))
Level: medium