2020 Practice Exam 1 MCQ Reflection

Table of Contents

tl;dr: I spent 2:21 on the exam (OT) and I need to review BI 3 as well as getting faster with logic-heavy problems (logic gates, etc.)

score

Correction #1

Image

To convert a decimal number to binary, follow these steps:

  1. Divide the decimal number by 2.
  2. Record the remainder (it will be either 0 or 1).
  3. Update the decimal number to be the quotient from the division.
  4. Repeat steps 1-3 until the decimal number is 0.
  5. The binary representation is the sequence of remainders read from bottom to top.

Here are some examples:

  • Converting 75 to binary:
    • 75 ÷ 2 = 37 remainder 1
    • 37 ÷ 2 = 18 remainder 1
    • 18 ÷ 2 = 9 remainder 0
    • 9 ÷ 2 = 4 remainder 1
    • 4 ÷ 2 = 2 remainder 0
    • 2 ÷ 2 = 1 remainder 0
    • 1 ÷ 2 = 0 remainder 1
    • Binary: 1001011
  • Converting 0 to binary:
    • Binary: 0
  • Converting 130 to binary:
    • 130 ÷ 2 = 65 remainder 0
    • 65 ÷ 2 = 32 remainder 1
    • 32 ÷ 2 = 16 remainder 0
    • 16 ÷ 2 = 8 remainder 0
    • 8 ÷ 2 = 4 remainder 0
    • 4 ÷ 2 = 2 remainder 0
    • 2 ÷ 2 = 1 remainder 0
    • 1 ÷ 2 = 0 remainder 1
    • Binary: 10000010

Correction #2

Image

  • Understanding the circuit logic:
    • The circuit consists of three logic gates: OR, AND, and a final AND gate.
    • The OR gate takes inputs A and B.
    • The first AND gate takes inputs C and D.
    • The final AND gate takes the outputs from the OR and AND gates.
  • Conditions for a TRUE output:
    • The OR gate outputs true if at least one of A or B is true.
    • The first AND gate outputs true only if both C and D are true.
    • The final AND gate outputs true if both inputs from the OR and first AND gates are true.
  • Evaluating the correct answer (C: A = false, B = true, C = true, D = true):
    • OR gate: A OR B = false OR true = true
    • First AND gate: C AND D = true AND true = true
    • Final AND gate: true AND true = true
    • Final output is true, so this is the correct choice.

Correction #3

wronganswer In this problem, I made the mistake of taking too long on this question and overthinking what it was trying to ask me. I should have “went with my gut” and chosen answer A. The reason why option C is incorrect is because it doesn’t account for the one extra loop iteration that happens in program b compared to program a.

Correction #4

conpresion In this question, the reason the answer isn’t D is because answer option D does not use any compression. However, in option A, both devices manage to compress and decompress without losing any data, which is why it is considered lossless.

Correction #5

sillymistake It doesn’t make any sense to store a duplicate copy of data at all in the case of an image, so it makes sense to choose answer option D in this example.