Comp Sci Unit 2 #8

The following code segment is used to determine whether a customer is eligible for a discount on a movie ticket.

val1 ← (NOT (category = "new")) OR (age ≥ 65)

val2 ← (category = "new") AND (age < 12)

If category is "new" and age is 20, what are the values of val1 and val2 as a result of executing the code segment?

• val1 = true, val2 = true

• val1 = true, val2 = false

• val1 = false, val2 = true

• val1 = false, val2 = false

Directions: The question or incomplete statement below is followed by four suggested answers or completions. Select the one that is best in each case.

A NAND gate is a type of logic gate that produces an output of false only when both of its two inputs are true. Otherwise, the gate produces an output of true . Which of the following Boolean expressions correctly models a NAND gate with inputs P and Q ?

• 
• 
• 
• 

The figure below shows a circuit composed of two logic gates. The output of the circuit is true.

Which of the following is a true statement about input A?

• Input A must be true.

• Input A must be false.

• Input A can be either true or false.

• There is no possible value of input A that will cause the circuit to have the output true.

To be eligible for a particular ride at an amusement park, a person must be at least 12 years old and must be between 50 and 80 inches tall, inclusive.

Let age represent a person’s age, in years, and let height represent the person’s height, in inches. Which of the following expressions evaluates to true if and only if the person is eligible for the ride?

• (age ≥ 12) AND ((height ≥ 50) AND (height ≤ 80))

• (age ≥ 12) AND ((height ≤ 50) AND (height ≥ 80))

• (age ≥ 12) AND ((height ≤ 50) OR (height ≥ 80))

• 
  (age ≥ 12) OR ((height ≥ 50) AND (height ≤ 80))

A large spreadsheet contains the following information about local restaurants. A sample portion of the spreadsheet is shown below.

• In column B, the price range represents the typical cost of a meal, where "lo" indicates under $10, "med" indicates $11 to $30, and "hi" indicates over $30.

• In column D, the average customer rating is set to -1.0 for restaurants that have no customer ratings.

A student wants to count the number of restaurants in the spreadsheet whose price range is $30 or less and whose average customer rating is at least 4.0. For a given row in the spreadsheet, suppose prcRange contains the price range as a string and avgRating contains the average customer rating as a decimal number.

Which of the following expressions will evaluate to true if the restaurant should be counted and evaluates to false otherwise?

• (avgRating ≥ 4.0) AND ((prcRange = "lo") AND (prcRange = "med"))

• (avgRating ≥ 4.0) AND ((prcRange = "lo") OR (prcRange = "med"))

• (avgRating ≥ 4.0) OR ((prcRange = "lo") AND (prcRange = "med"))

• (avgRating ≥ 4.0) OR ((prcRange = "lo") OR (prcRange = "med"))

To qualify for a particular scholarship, a student must have an overall grade point average of 3.0 or above and must have a science grade point average of over 3.2. Let overallGPA represent a student’s overall grade point average and let scienceGPA represent the student’s science grade point average. Which of the following expressions evaluates to true if the student is eligible for the scholarship and evaluates to false otherwise?

• (overallGPA > 3.0) AND (scienceGPA > 3.2)

• (overallGPA > 3.0) AND (scienceGPA ≥ 3.2)

• (overallGPA ≥ 3.0) AND (scienceGPA > 3.2)

• (overallGPA ≥ 3.0) AND (scienceGPA ≥ 3.2)

In a certain country, a person must be at least 16 years old to drive a car and must be at least 18 years old to vote. The variable age represents the age of a person as an integer.

Which of the following expressions evaluates to true if the person is old enough to drive but not old enough to vote, and evaluates to false otherwise?

1. (age ≥ 16) AND (age ≤ 18)

2. (age ≥ 16) AND (NOT(age ≥ 18))

3. (age < 18) AND (NOT(age < 16))

• 
  II only

• I and II only

• I and III only

• 
  II and III only

The diagram below shows a circuit composed of three logic gates. Each gate takes two inputs and produces a single output.

For which of the following input values will the circuit have an output of true ?

• A = true,  B = true,  C = true,  D = false

• A = true,  B = false, C = false, D = true

• A = false, B = true,  C = true,  D = true

• A = false, B = false, C = true,  D = true

To attend a particular camp, a student must be either at least 13 years old or in grade 9 or higher, but must not yet be 18 years old. Let age represent a student’s age and let grade represent the student’s grade level. Which of the following expressions evaluates to true if the student is eligible to attend the camp and evaluates to false otherwise?

• ((age ≥ 13) OR (grade ≥ 9)) AND (age ≤ 18)

• ((age ≥ 13) OR (grade ≥ 9)) AND (age < 18)

• ((age ≥ 13) OR (grade ≥ 9)) OR (age ≤ 18)

• ((age ≥ 13) OR (grade ≥ 9)) OR (age < 18)

Let n be an integer value. Which of the following expressions evaluates to true if and only if n is a two-digit integer (i.e., in the range from 10 to 99, inclusive)?

• n = (n MOD 100)

• (n ≥ 10) AND (n < 100)

• (n < 10) AND (n ≥ 100)

• (n > 10) AND (n < 99)