Table:
0
A
B
C
D
E
F
G
1
Landfill
Location
Acres
Opened
Capacity
Status
Rehab Period
2
Gin Drinkers Bay
Kwai Tsing District
29
1960
3.5 million tonnes
Closed
1999–2000
3
Ngau Tam Mei
Yuen Long District
2
1973
0.15 million tonnes
Closed
1999–2000
4
Shuen Wan
Tai Po District
50
1973
15 million tonnes
Closed
1996–1997
5
Ma Tso Lung
North District
2
1976
0.2 million tonnes
Closed
1999–2000
6
Ngau Chi Wan
Wong Tai Sin District
8
1976
0.7 million tonnes
Closed
1997–1998
7
Sai Tso Wan
Kwun Tong District
9
1978
1.6 million tonnes
Closed
1997–1998
8
Siu Lang Shui
Tuen Mun District
12
1978
1.2 million tonnes
Closed
1999–2000
9
Tseung Kwan O Stage I
Sai Kung District
68
1978
15.2 million tonnes
Closed
1997–1999
10
Ma Yau Tong West
Kwun Tong
6
1979
6 million tonnes
Closed
1997–1998
11
Ma Yau Tong Central
Kwun Tong
11
1981
1.0 million tonnes
Closed
1997–1998
12
Pillar Point Valley
Tuen Mun District
38
1983
13 million tonnes
Closed
2004–2006
13
Jordan Valley
Kwun Tong
11
1986
1.5 million tonnes
Closed
1997–1998
14
Tseung Kwan O Stage II-III
Sai Kung District
42
1988
12.6 million tonnes
Closed
1997–1999

Questions and formulas:
Question: What is the total number of acres at Sai Tso Wan, opening before 1978?
Formula: SUM(FILTER(C1, (A1="sai tso wan")*(D1<1978)))
Formula2: SUM(FILTER(C2:C14, (A2:A14="sai tso wan")*(D2:D14<1978)))
Level: easy