APCSP Practice Test 2025 LATEST
UPDATE
What is the best explanation for digital data is represented in computers in binary?
A. The binary number system is the only number system flexible enough to allow for
representing data other than numbers.
B. As a consequence of history: early pioneers of computing were making secret codes
in binary, and this simply evolved into modern computing.
C. It's impossible to build a computer machine that uses anything but binary to
represent numbers.
D. It's easier, cheaper, and more reliable to build machines and devices that only have
to distinguish between binary states. - ANSWER D. It's easier, cheaper, and more
reliable to build machines and devices that only have to distinguish between binary
states.
What is the 4-bit number for the decimal number ten (10)?
A. 0010
B. 1010
C. 0110
D. 0101 - ANSWER B. 1010
What is the minimum number of bits you would need to encode the 26 letters of the
alphabet plus a space - a total of 27 characters?
A. 2 bits
B. 3 bits
C. 5 bits
D. 6 bits - ANSWER C. 5 bits
The next questions refers to the hexidecimal (base 16) number system:
Number bases, including binary, decimal, and hexadecimal, are used to view and
represent digital data. Which of the following is NOT true about representing digital
data?
A. At one of the lowest levels of abstraction, all digital data can be represented in binary
using only combinations of the digits zero and one.
B. Hexadecimal is used to represent digital data because hexadecimal representation
uses only 1 digit to represent groups of 4 binary digits.
C. Binary can be used to represent more complex, higher level abstractions, including
but not limited to numbers, characters, and colors.
,D. There is a limit to the number of things that can be represented in binary data at
which point switching to hexadecimal representation is necessary. - ANSWER D. There
is a limit to the number of things that can be represented in binary data at which point
switching to hexadecimal representation is necessary.
Consider the following numbers given in Binary (BIN), Decimal (DEC), and Hexadecimal
(HEX) representations:
BIN: 1110
DEC: 13
HEX: F
Which of the following lists the numbers in order from least to greatest?
A. BIN: 1110, DEC: 13, HEX: F
B. DEC: 13, BIN: 1110, HEX: F
C. DEC: 13, HEX: F, BIN: 1110
D. HEX: F, DEC: 13, BIN: 1110 - ANSWER B. DEC: 13, BIN: 1110, HEX: F
A middle school is expanding to open a high school next year, doubling the total number
of students. The school keeps a database in which each student's unique ID number is
stored as an 8 bit number called studentID. Before the arrival of the new students
almost every 8 bit number has already been assigned to a student. Which is the most
accurate description of how the school could modify the way studentID is represented in
the database to ensure each incoming student receives a unique ID?
A. Add a bit to studentID to double the number of IDs that the database can represent.
B. Double the number of bits in studentID to double the number of IDs that the
databases can represent.
C. Keep using an 8-bit number for studentID but reserve the first bit to indicate middle
school or high school.
D. Remove a bit from studentID to make room for incoming students. - ANSWER A.
Add a bit to studentID to double the number of IDs that the database can represent.
NOTE:
Doubling the number of bits would obviously make room for more student IDs, but it's
inaccurate to say that that doubles the number of possible IDs. If the number of bits
went from 8 to 16, it's 256 TIMES AS MANY possible ids. 8 bits = 256 values and 16
bits = 65,536 IDs.
A user clicks on a website, and it begins to load immediately, but it takes a long time to
load completely and pictures appear slowly, one by one. Which of the following is
demonstrated through this situation?
A. High bandwidth, high latency
B. Low bandwidth, high latency
, C. High bandwidth, low latency
D. Low bandwidth, low latency - ANSWER D. Low bandwidth, low latency
8 bits is enough to represent 256 different numbers. How many total bits do you need to
represent 512 (twice as many) numbers?
A. 9 bits
B. 10 bits
C. 16 bits
D. 17 bits - ANSWER A. 9 bits
The next question refers to hexadecimal which is a base-16 number system - a number
system that uses one of 16 possible digits for each place value.
ASCII is a character-encoding scheme that uses a numeric value to represent each
character. For example, the uppercase letter "G" is represented by the decimal (base
10) value 71. A partial list of characters and their corresponding ASCII values are
shown in the table below.
Decimal ASCII
80 P
81 Q
82 R
83 S
84 T
85 U
86 V
87 W
88 X
89 Y
90 Z
A. A
B. L
C. V
D. Y - ANSWER C. V
NOTE:
In order to calculate the value of the base-16 number 56, it is 5*16^1 + 6*16^0 = 86,
which maps to 'V' in the table
A video-streaming Web site uses 32-bit integers to count the number of times each
video has been played. In anticipation of some videos being played more times than
can be represented with 32 bits, the Web site is planning to change to 64-bit integers for
