Table:
0
A
B
C
D
E
F
1
product id
product type code
daily hire cost
product name
product description
products for hire
2
1
Cutlery
26.15
Book collection C
Anna Karenina
3
2
Cutlery
15.62
Book collection B
War and Peace
4
3
Cutlery
39.73
Book collection A
The Great Gatsby
5
4
Din_Plates
18.5
DVD collection A
Twilight
6
5
Cutlery
39.58
DVD collection B
One Hundred Years of Solitude

Questions and formulas:
Question: Total number of product types 
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B6))
Level: easy
Question: the names, descriptions and ids of cutlery products that cost less than 20 a day to hire
Formula: LET(query1,LET(query1,FILTER(A1:F1,B1="cutlery"),SUMMARIZE(HSTACK(CHOOSECOLS(query1,4,5,1)),SUMX(CHOOSECOLS(query1,3)))),FILTER(query1,CHOOSECOLS(query1,4)<20))
Formula2: LET(query1,LET(query1,FILTER(A2:F6,B2:B6="cutlery"),SUMMARIZE(HSTACK(CHOOSECOLS(query1,4,5,1)),SUMX(CHOOSECOLS(query1,3)))),FILTER(query1,CHOOSECOLS(query1,4)<20))
Level: hard
Question: the count of product types
Formula: ROWS(UNIQUE(B1))
Formula2: ROWS(UNIQUE(B2:B6))
Level: easy
Question: the names, descriptions and ids of cutlery products with daily hire cost under 20
Formula: LET(query1,LET(query1,FILTER(A1:F1,B1="cutlery"),SUMMARIZE(HSTACK(CHOOSECOLS(query1,4,5,1)),SUMX(CHOOSECOLS(query1,3)))),FILTER(query1,CHOOSECOLS(query1,4)<20))
Formula2: LET(query1,LET(query1,FILTER(A2:F6,B2:B6="cutlery"),SUMMARIZE(HSTACK(CHOOSECOLS(query1,4,5,1)),SUMX(CHOOSECOLS(query1,3)))),FILTER(query1,CHOOSECOLS(query1,4)<20))
Level: hard