Unit 3

A certain game keeps track of the maximum and minimum scores obtained so far. If num represents the most recent score obtained, which of the following algorithms correctly updates the values of the maximum and the minimum?

• If num is greater than the minimum, set the minimum equal to num. Otherwise, if num is greater than the maximum, set the maximum equal to num.

• If num is less than the minimum, set the minimum equal to num. Otherwise, if num is greater than the maximum, set the maximum equal to num.

• If num is less than the minimum, set the minimum equal to num. Otherwise, if num is less than the maximum, set the maximum equal to num.

• If num is greater than the minimum, set the minimum equal to num. Otherwise, if num is less than the maximum, set the maximum equal to num.

Look above

• Step 1:

  Keep moving forward, one square at a time, until the square  to the right of the robot is black.

  Step 2:

  Turn right and move one  square forward.

  Step 3:

  Repeat steps 1 and 2 three more times.

• Step 1:

  Keep moving forward, one square at a time, until  the square to   the right of the robot is no longer black.

  Step 2:

  Turn right and move one      square forward.

    Step 3: Repeat steps 1 and 2 three more times.

• Step 1:

  Move forward three squares.

  Step 2:

  Turn right and move one square forward.

  Step 3: If the square to the right of the robot is black, repeat steps 1 and 2.

• Step 1:

  Move forward three squares.

  Step 2:

  Turn right and move one square forward.

  Step 3:

  If the square to the right of the robot is not black, repeat steps 1 and 2.

A programmer is creating an algorithm that will be used to turn on the motor to open the gate in a parking garage. The specifications for the algorithm are as follows.

• The gate should not open when the time is outside of business hours.

• The motor should not turn on unless the gate sensor is activated.

• The motor should not turn on if the gate is already open.

Which of the following algorithms can be used to open the gate under the appropriate conditions?

Responses

• Check if the time is outside of business hours. If it is, check if the gate sensor is activated. If it is, check if the gate is closed. If it is, turn on the motor.

• Check if the time is during business hours. If it is, check if the gate sensor is activated. If it is, check if the gate is open. If it is, turn on the motor.

• Check if the time is during business hours. If it is, check if the gate sensor is activated. If it is not, check if the gate is open. If it is not, turn on the motor.

• Check if the time is during business hours. If it is, check if the gate sensor is activated. If it is, check if the gate is open. If it is not, turn on the motor.

Three different numbers need to be placed in order from least to greatest. For example, if the numbers are ordered 9, 16, 4, they should be reordered as 4, 9, 16. Which of the following algorithms can be used to place any three numbers in the correct order?

• Three different numbers need to be placed in order from least to greatest. For example, if the numbers are ordered 9, 16, 4, they should be reordered as 4, 9, 16. Which of the following algorithms can be used to place any three numbers in the correct order?

• If the first number is greater than the middle number, swap them. Then, if the middle number is greater than the last number, swap them.

• If the first number is greater than the middle number, swap them. Then, if the middle number is greater than the last number, swap them. Then, if the first number is greater than the last number, swap them.

• If the first number is greater than the middle number, swap them. Then, if the middle number is greater than the last number, swap them. Then, if the first number is greater than the middle number, swap them.

A teacher has a goal of displaying the names of 2 students selected at random from a group of 30 students in a classroom. Any possible pair of students should be equally likely to be selected. Which of the following algorithms can be used to accomplish the teacher’s goal?

• Step 1:

  Assign each student a unique integer from 1 to 30.

  Step 2:

  Generate a random integer n from 1 to 15.

  Step 3:

  Select the student who is currently assigned integer n and display the student’s name.

  Step 4:

  Generate a new random integer n from 16 to 30.

  Step 5:

  Select the student who is currently assigned integer n and display the student’s name.

• Step 1:

  Assign each student a unique integer from 1 to 30.

  Step 2:

  Generate a random integer n from 1 to 30.

  Step 3:

  Select the student who is currently assigned integer n and display the student’s name.

  Step 4:

  Generate a new random integer n from 1 to 30.

  Step 5:

  Select the student who is currently assigned integer n and display the student’s name.

• Step 1:

  Assign each student a unique integer from 1 to 30.

  Step 2:

  Generate a random odd integer n from 1 to 29.

  Step 3:

  Select the student who is currently assigned integer n and display the student’s name.

  Step 4:

  Generate a new random even integer n from 2 to 30.

  Step 5:

  Select the student who is currently assigned integer n and display the student’s name.

• Step 1:

  Assign each student a unique integer from 1 to 30.

  Step 2:

  Generate a random integer n from 1 to 30.

  Step 3:

  Select the student who is currently assigned integer n and display the student’s name.

  Step 4:

  The student who was selected in the previous step is assigned 0. All other students are reassigned a unique integer from 1 to 29.

  Step 5:

  Generate a new random integer n from 1 to 29.

   Step 6:

  Select the student who is currently assigned integer n and display the student’s name.

The variable age is to be used to represent a person’s age, in years. Which of the following is the most appropriate data type for age ?

• Boolean

• number

• string

• list

The variable isOpen is to be used to indicate whether or not a store is currently open. Which of the following is the most appropriate data type for isOpen ?

• Boolean

• Number

• String

• List

A teacher is writing a code segment that will use variables to represent a student’s name and whether or not the student is currently absent. Which of the following variables are most appropriate for the code segment?

• A string variable named s and a Boolean variable named a

• A string variable named s and a numeric variable named n

• A string variable named studentName and a Boolean variable named isAbsent

• A string variable named studentName and a numeric variable named numAbsences

In a certain game, the integer variable bonus is assigned a value based on the value of the integer variable score.

• If score is greater than 100, bonus is assigned a value that is 10 times score.

• If score is between 50 and 100 inclusive, bonus is assigned the value of score.

• If score is less than 50, bonus is assigned a value of 0.

Which of the following code segments assigns bonus correctly for all possible integer values of score ?

Select two answers.

• IF(score > 100)

  {

  bonus ← score * 10

  }

  ELSE

  {

  IF(score ≥ 50)

  {

  bonus ← score

  }

  ELSE

  {

  bonus ← 0

  }

  }

• IF(score ≥ 50)

  {

  IF(score > 100)

  {

  bonus ← score * 10

  }

  ELSE

  {

  bonus ← 0

  }

  }

  ELSE

  {

  bonus ← score

  }

• IF(score < 50)

  {

  bonus ← 0

  }

  ELSE

  {

  IF(score ≥ 50)

  {

  bonus ← score

  }

  ELSE

  {

  bonus ← score * 10

  }

  }

• IF(score < 50)

  {

  bonus ← 0

  }

  ELSE

  {

  IF(score > 100)

  {

  bonus ← score * 10

  }

  ELSE

  {

  bonus ← score

  }

  }

The cost of a customer’s electricity bill is based on the number of units of electricity the customer uses.

• For the first 25 units of electricity, the cost is $5 per unit.

• For units of electricity after the first 25, the cost is $7 per unit.

Which of the following code segments correctly sets the value of the variable cost to the cost, in dollars, of using numUnits units of electricity?

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