Table:
0
A
B
C
D
E
1
customer id
name
level of membership
age
customer
2
1
Gonzalo Higuaín 
8
35
3
2
Guti Midfielder
5
28
4
3
Arjen Robben
1
27
5
4
Raúl Brown
2
56
6
5
Fernando Gago
6
36
7
6
Rafael van der Vaart
1
25

Questions and formulas:
Question: Find the names of the visitors whose membership level is higher than 4, and order the results by the membership level from high to low
Formula: SORT(LET(query1,SUMMARIZE(B1,SUMX(C1)),FILTER(query1,CHOOSECOLS(query1,2)>4)), 2, -1)
Formula2: SORT(LET(query1,SUMMARIZE(B2:B7,SUMX(C2:C7)),FILTER(query1,CHOOSECOLS(query1,2)>4)), 2, -1)
Level: hard
Question: What is the average age of the visitors whose membership level is not higher than 4?
Formula: AVERAGE(FILTER(D1,C1<=4))
Formula2: AVERAGE(FILTER(D2:D7,C2:C7<=4))
Level: easy
Question: Find the name and membership level of the visitors whose membership level is higher than 4, and sort by their age from old to young.
Formula: SORTBY(CHOOSE({1,2},FILTER(B1,C1>4),FILTER(C1,C1>4)),FILTER(D1,C1>4),-1)
Formula2: SORTBY(CHOOSE({1,2},FILTER(B2:B7,C2:C7>4),FILTER(C2:C7,C2:C7>4)),FILTER(D2:D7,C2:C7>4),-1)
Level: hard
Question: the average age of visitors that have membership level <= 4.
Formula: AVERAGE(FILTER(D1, C1<=4))
Formula2: AVERAGE(FILTER(D2:D7, C2:C7<=4))
Level: easy
Question: the average age of visitors whose membership level <= 4.
Formula: AVERAGE(FILTER(D1, C1<=4))
Formula2: AVERAGE(FILTER(D2:D7, C2:C7<=4))
Level: easy