Table:
0
A
B
C
D
E
1
Series
Start date
End date
Episodes
Average viewers (millions)
2
1
22 August 2009
3 October 2009
7
5.09
3
2
19 September 2010
2 January 2011
12
4.95
4
3
3 April 2011
11 June 2011
9
3.72
5
4
30 October 2011
31 December 2011
9
4.2
6
5
14 April 2012
23 December 2012
9
3.26
7
6
2 March 2013
30 June 2013
13
3.66

Questions and formulas:
Question: When did series 6 start?
Formula: LET(query1,SUMMARIZE(B1,SUMX(A1)),FILTER(query1,CHOOSECOLS(query1,2)=6))
Formula2: LET(query1,SUMMARIZE(B2:B7,SUMX(A2:A7)),FILTER(query1,CHOOSECOLS(query1,2)=6))
Level: hard
Question: What series had an average of 3.72 million people watching it?
Formula: SUM(FILTER(A1, E1=3.72))
Formula2: SUM(FILTER(A2:A7, E2:E7=3.72))
Level: easy
Question: How many different end dates are there for the series seen by 4.2 million people?
Formula: LET(query1,SUMMARIZE(C1,SUMX(E1)),FILTER(query1,CHOOSECOLS(query1,2)=4.2))
Formula2: LET(query1,SUMMARIZE(C2:C7,SUMX(E2:E7)),FILTER(query1,CHOOSECOLS(query1,2)=4.2))
Level: hard