Discrete Math Chapter 1 exam review


Question 1       Write a negation for the statement.
Charlie plays football.
Question options:
            Charlie does not like football.
            Not Charlie plays football.
            Charlie does not play football.
            Charlie plays basketball.
Question 2       Write a negation for the statement.
My brother is asleep.
Question options:
            My sister is awake.
            My brother is not asleep.
            My sister is asleep.
            The person who is asleep is not my brother.
Question 3       Write a negation for the statement.
That athlete wants to be a musician.
Question options:
            That musician wants to be an athlete.
            That musician does not want to be an athlete.
            That athlete does not want to be a musician.
            That athlete is not a musician.
Question 4       Translate the symbolic compound statement into words.
Let p represent the statement "Her name is Lisa" and let q represent the statement "She lives in Chicago."
p ^ q
Question options:
            Her name is Lisa and she doesn't live in Chicago.
            Her name is Lisa or she lives in Chicago.
            Her name is Lisa and she lives in Chicago.
            If her name is Lisa, she lives in Chicago.
Question 5       Let p represent the statement, "Jim plays football", and let q represent "Michael plays basketball". Convert the compound statements into symbols.
Jim does not play football and Michael does not play basketball.
Question options:
            ~p V ~q
~p ^ ~q
            p V q
            p ^ q
Correct answer is B
Question 6       Let p represent the statement, "Jim plays football", and let q represent "Michael plays basketball". Convert the compound statements into symbols.
Jim does not play football and Michael plays basketball.
Question options:
            p ^ q
            ~(p ^ q)
            ~p ^ q
            ~p V q
Correct answer is C
Question 7       Construct a truth table for the statement.
~p ^ ~q
Question options:
















Correct answer is D
Question 8       Construct a truth table for the statement.
(p ^ ~q) ^ t
Question options:














Correct answer is B
Question 9        Construct a truth table for the statement.
(t ^ p) V (~t ^ ~p)
Question options:

Correct answer is D
Question 10     Write a negation of the statement.
No fifth graders play soccer.
Question options:
            Everybody does not play soccer.
            Everybody plays soccer.
            Some fifth graders play soccer.
            Fifth graders play soccer.
Question 11     Write a negation of the statement.
Some people don't like walking.
Question options:
            Nobody likes walking.
            Some people like walking.
            All people like walking.
            Some people don't like driving.
Question 12     Write the compound statement in symbols.
Let r = "The food is good," p = "I eat too much," q = "I'll exercise."
If the food is good and if I eat too much, then I'll exercise.
Question options:
  
         






Correct answer is C
Question 1       Write the statement as an equivalent statement that does not use the if . . . then connective. Remember that p → q is equivalent to ~p  q.
If the sun comes out Tuesday, the roses will open.
The sun comes out Tuesday and the roses will not open.
The sun does not come out Tuesday or the roses will not open.
The sun does not come out Tuesday and the roses will not open.
The sun does not come out Tuesday or the roses will open.
Question 2                   Write the indicated statement. Use De Morgan’s Laws if necessary.
If I pass, I'll party.
Contrapositive
            If I don't pass, I won't party.
            If I party, then I passed.
            I'll party if I pass.
            If I don't party, I didn't pass.
Question 3       Write the indicated statement. Use De Morgan’s Laws if necessary.
If you like me, then I like you.
Converse
            If I like you, then you like me.
            I like you if you don't like me.
            If you don't like me, I don't like you.
            I don't like you if you don't like me.
Question 4       Write the indicated statement. Use De Morgan’s Laws if necessary.
If it is love, then it is blind.
Contrapositive
            If it is blind then it is love.
            If it is blind then it is not love.
            It is blind if it is love.
            If it is not blind, then it is not love.
Question 5       Write the indicated statement. Use De Morgan’s Laws if necessary.
If the moon is out, then we will start a campfire and we will roast marshmallows.
Inverse
Question options:
            If the moon is not out, then we will start a campfire but we will not roast marshmallows.
            If the moon is not out, then we will not start a campfire or we will not roast marshmallows.
            If we do not start a campfire or we do not roast marshmallows, then the moon is not out.
            If we start a campfire and we roast marshmallows, then the moon is out.
Question 6       Write the indicated statement. Use De Morgan’s Laws if necessary.
If the chores are done, then we will go to the carnival and we will eat cotton candy.
Contrapositive
Question options:
            If we do not go to the carnival or we do not eat cotton candy, then the chores are not done.
            If the chores are not done, then we will not go to the carnival or we will not eat cotton candy.
            If we go to the carnival and we eat cotton candy, then the chores are done.
            If we do not go to the carnival and we do not eat cotton candy, then the chores are not done.
Question 7       Use one of De Morgan's laws to write the negation of the statement.
10 + 2 = 12 and 8 - 3 ≠ 5
Question options:
            10 + 2 ≠ 12 and 8 - 3 = 5
            10 + 2 = 12 and 8 - 3 = 5
            10 + 2 = 12 or 8 - 3 ≠ 5
            10 + 2 ≠ 12 or 8 - 3 = 5
Question 8       Use a truth table to decide if the two statements are equivalent.
~p  ~q; ~(p  q)
Question options:
            True
            False
Question 9       Use a truth table to decide if the two statements are equivalent.
~q  p; ~q → p
Question options:
            True
            False
Question 10     Use a truth table to decide if the two statements are equivalent.
q → p; p → q
Question options:
            True
            False

1.      All fish can dream. Any dead animal is unable to dream. All live animals have a heartbeat.
a)      Any dead animal has no heartbeat.
b)      All live animals can dream.
c)      All fish have a heartbeat.
d)     Any dead fish can dream.

2.      Use the premises to give a conclusion that yields a valid argument.
If you pay taxes, then you are a good citizen. People who do not pay taxes do not receive a tax bill. If it is April, then Mark receives a tax bill.
a)      Mark did not receive a tax bill.
b)      Mark is not a good citizen.
c)      Mark is a good citizen.
d)     Mark did not pay taxes.

3.      Use the premises to give a conclusion that yields a valid argument:
Students who watch television while doing homework lower their grades. Students who lower their grades get grounded. Grounded people will not be allowed to watch television.
a)      Students who watch television while doing homework will not be allowed to watch television.
b)      Students who are grounded watch television while doing homework.
c)      Students who watch television will be grounded.
d)     Students who watch television will not be allowed to watch television.

4.      Write the statement symbolically.
Some lights are green.
A) ∀x [l(x) → g(x)]
B) x [l(x) g(x)]
C) x [l(x) g(x)]
D) x [l(x) → g(x)]
5.      Write the statement symbolically.
All refrigerators are appliances.
A) ∀x [r(x) a(x)]
B) x [r(x) a(x)]
C) x [r(x) → a(x)]
D) x [r(x) a(x)]
6.      Write the statement symbolically.
No dogs can read.
A) x [d(x) ~r(x)]
B) x [~d(x) r(x)]
C) x [d(x) ~r(x)]
D) x [~d(x) r(x)]




7.      Write the statement symbolically.
Some cats can sing.
A) ∀x [c(x) s(x)]
B) x [c(x) s(x)]
C) x [c(x) s(x)]
D) x [c(x) s(x)]
8.      Write the negative of the statement.
x [g(x) → c(x)
A) x [g(x) ~c(x)]
B) x [c(x) → g(x)]
C) x [g(x) → ~c(x)]
D) x [g(x) ~c(x)]
9.      Write the negative of the statement.
x [m(x) n(x)]
A) ∃x [m(x) → ~n(x)]
B) x [~m(x) → n(x)]
C) x [~m(x) → n(x)]
D) x [m(x) → ~n(x)]
10.  Determine if the argument is valid.
All business expenses are covered by the company.
____________________________________________
This expense is a business expense.
a)      Invalid             b) Valid

11.  Determine if the argument is valid.
All businesses are subject to safety inspections.
___________________________
This restaurant is a business.
a)      Invalid                         b)Valid

12.  Determine if the argument is valid.
All astronauts are healthy.
______________________
Lawrence is not healthy.
a)      Valid   b) Invalid

13.  Determine if the argument is valid.
All businessmen wear suits.
________________________
Aaron wears a suit.
a)      Valid   b) Invalid

14.  The argument has a true conclusion. Identify the argument as valid or invalid.
Eric is older than Camille.
_____________________
Todd is younger than Eric.
a)      Invalid             b) Valid
15.  The argument has a true conclusion. Identify the argument as valid or invalid.
A square is a parallelogram.
______________________
A square has four sides.

a) Invalid   b) Valid

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