Table:
0
A
B
C
D
E
1
State (class)
Vacator
Reason for change
Successor
Date of successors formal installation
2
Hawaii (1)
New seats
Hawaii achieved statehood August 21, 1959.
Hiram Fong (R)
August 21, 1959
3
Hawaii (3)
New seats
Hawaii achieved statehood August 21, 1959.
Oren E. Long (D)
August 21, 1959
4
North Dakota (1)
William Langer (R)
Died November 8, 1959
Clarence N. Brunsdale (R)
November 19, 1959
5
Oregon (2)
Richard L. Neuberger (D)
Died March 9, 1960
Hall S. Lusk (D)
March 16, 1960
6
North Dakota (1)
Clarence N. Brunsdale (R)
Successor elected August 7, 1960.
Quentin N. Burdick (D)
August 8, 1960
7
Missouri (3)
Thomas C. Hennings, Jr. (D)
Died September 13, 1960
Edward V. Long (D)
September 23, 1960

Questions and formulas:
Question: What is every reason for change for the date of successors installation is March 16, 1960?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,E1="March 16, 1960"),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E7,E2:E7="March 16, 1960"),3))
Level: medium
Question: Who is every vacator if date of successors formal installation is August 8, 1960?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,E1="August 8, 1960"),2))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E7,E2:E7="August 8, 1960"),2))
Level: medium