Score: 61/66

Question My Answer Correct Answer
Which of the following best describes one of the benefits of using an iterative and incremental process of program development? It enables programmers to create programs that use the lowest-level abstractions available.
Explanation: The use of low-level abstractions is unrelated to the development process used.		 The ability to provide data transmission even when some connections have failed.
Explanation:Routers on the Internet are able to move packets through various paths to reach their final destination, even when some connections have failed. This characterizes the fault-tolerant nature of routing.
A social media site allows users to send messages to each other. A group of researchers gathered user data for the first 10 years of the site’s existence. Some of the data are summarized in the table below, along with some of the company milestones. The researchers noticed that the total number of registered users appears to be increasing at about a constant rate. If this pattern continues, which of the following best approximates the total number of registered users, in millions, in year 12 (two years after the last entry in the table) ?


 30.6

Explanation:
The approximation 30.6 million would be a better estimate for year 11.		 31.2

The total number of registered users appears to be increasing by about 0.5 million each year, so in year 12, the number of users can be approximated at 31.2 million (30.2 + 0.5 + 0.5).
Image Program A and program B display a different number of values. Program A and program B display the same number of values, but the values differ.

Explanation: This option is correct. The programs each display ten values, but each value displayed by program B is one greater than the
corresponding value from program A. Program A displays 1 2 3 4 5 6 7 8 9 10 and program B displays 2 3 4 5 6 7 8 9 10 11.
The grid below contains a robot represented as a triangle, initially facing up. The robot can move into a white or gray square but cannot move into a black region. The code segment below uses the procedure One word, Goal Reached, which evaluates to true if the robot is in the gray square and evaluates to falseotherwise.
 Image

Explanation: This code segment moves the robot up and down between its initial location and the square above its initial location.		 Image

Explanation: This code segment rotates right whenever there is an open square to the right. The robot will move forward from its initial location to the upper-left corner of the grid, then rotate right, then move forward to the upper-right corner of the grid, then rotate right, then move down two squares, then rotate right, then move forward to the gray square.
Internet protocol version 4 (IPv4) represents each IP address as a 32-bit binary number. Internet protocol version 6 (IPv6) represents each IP address as a 128-bit binary number. Which of the following best describes the result of using 128-bit addresses instead of 32-bit addresses? 2 to the fourth power times as many addresses are available. 2 raised to the ninety sixth power times as many addresses are available.
Explanation: With 32-bit addressing, IPv4 has 2 raised to the thirty second power possible addresses. With 128-bit addressing, IPv6 has 2 raised to the one hundred twenty eighth power possible addresses. Since 2 raised to the thirty second power times 2 raised to the ninety sixth power equals 2 raised to the one hundred twenty eighth power, IPv6 has 2 raised to the ninety sixth power times as many possible addresses as IPv4.