自測試題二（2）

Questions 3-8
    On each day of the Monday through Friday workweek，
    exactly two of three employees-George， Hilda， and
    Irene-must remain on duty in the office to answer tele-
    phones during the noon to 1 p.m. lunch break. In the
    scheduling of telephone duty the following constraints
    must be met：
    Hilda and Irene have telephone duty together on
    Tuesday.
    George and Hilda have telephone duty together on
    Thursday.
    No one can have telephone duty on more than four of the
    five days of the week.
    3.Which of the following can be the week's telephone
    duty schedule？
    Monday Tuesday Wednesday Thursday Friday
    （A） George George Hilda George Hilda
    Hilda Irene Irene Hilda Irene
    （B） George Hilda George Hilda George
    Hilda Irene Hilda Irene Irene
    （C） George Hilda George George George
    Irene Irene Hilda Hilda Hilda
    （D） Hilda Hilda George George Hilda
    Irene Irene Hilda Hilda Irene
    （E） Hilda Hilda George George George
    Irene Irene Hilda Irene Irene
    4.If Hilda has telephone duty for exactly two days of
    the week， which of the following must be true？
    （A）George and Irene have telephone duty together
    on Wednesday.
    （B）George and Hilda have telephone duty together
    on Friday.
    （C）Hilda and Irene have telephone duty together on
    Wednesday.
    （D）Hilda and Irene have telephone duty together on
    Friday.
    （E）Irene has telephone duty for exactly three days
    of the week.
    5.If Hilda and Irene have telephone duty together on
    Monday and on Wednesday， which of the following
    must be true？
    （A）George and Hilda have telephone duty together
    on Friday.
    （B）George and Irene have telephone duty together
    on Friday.
    （C）George has telephone duty on exactly three of
    the days of the week.
    （D）Hilda has telephone duty on exactly three of the
    days of the week.
    （E）Irene has telephone duty on exactly three of the
    days of the week.
    6.If George and Hilda have telephone duty together on
    Monday and George and Irene have telephone duty
    together on Friday， any of the following can be true
    EXCEPT：
    （A）George and Hilda have telephone duty together
    on Wednesday.
    （B）George and Irene have telephone duty together
    on Wednesday.
    （C）George has telephone duty for four days of the
    week.
    （D）Irene has telephone duty for four days of the
    week.
    （E）Hilda and Irene have telephone duty together for
    two days of the week.
    7.If there is one pair of employees who have telephone
    duty together for three of the five days， which of the
    following must be true？
    （A）George has telephone duty on Wednesday.
    （B）George and Hilda have telephone duty together
    for three days of the week.
    （C）Hilda and Irene have telephone duty together for
    three days of the week.
    （D）One of the three employees has telephone duty
    for exactly two days of the week.
    （E）Exactly one of the workers has telephone duty
    for exactly three days of the week.
    8.Any of the following can be true EXCEPT：
    （A）One pair of employees has telephone duty
    together for exactly one day of the week
    （B）One pair of employees has telephone duty
    together for exactly four days of the week
    （C）The pair of employees that has telephone duty
    together on Monday also has telephone duty
    together on Wednesday
    （D）The pair of employees that has telephone duty
    together on Tuesday also has telephone duty
    together on Wednesday
    （E）The pair of employees that has telephone duty
    together on Thursday also has telephone duty
    together on Friday