Question 1mediummultiple choice
Full question →- A
10
Why wrong: b not used.
- B
5
Why wrong: a is 10, not b.
- C
15
Uses default b=5.
- D
Error
Why wrong: Function is valid.
Question 179 of 510
PCEP Computer Programming and Python Fundamentals Practice Question
This PCEP practice question tests your understanding of computer programming and python fundamentals. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A function is defined as:
def add(a, b=5):
return a + bWhat is the result of add(10)?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
15
The function `add(a, b=5)` defines a default value of 5 for parameter `b`. When called as `add(10)`, the argument 10 is assigned to `a`, and `b` uses its default value of 5. The function returns `10 + 5 = 15`, making option C correct.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
10
Why it's wrong here
b not used.
- ✗
5
Why it's wrong here
a is 10, not b.
- ✓
15
Why this is correct
Uses default b=5.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Error
Why it's wrong here
Function is valid.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Python Institute often tests the misconception that default parameters are required or that omitting them causes an error, leading candidates to pick 'Error' (option D) when the function is actually called correctly with a single argument.
Detailed technical explanation
How to think about this question
In Python, default parameter values are evaluated only once at function definition time (not at each call), which is important when using mutable defaults like lists. Here, the default `b=5` is an immutable integer, so no aliasing issues arise. This concept is fundamental for writing flexible functions with optional parameters, commonly used in APIs and library code to reduce boilerplate.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the PCEP exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this PCEP question test?
Computer Programming and Python Fundamentals — This question tests Computer Programming and Python Fundamentals — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 15 — The function `add(a, b=5)` defines a default value of 5 for parameter `b`. When called as `add(10)`, the argument 10 is assigned to `a`, and `b` uses its default value of 5. The function returns `10 + 5 = 15`, making option C correct.
What should I do if I get this PCEP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 30, 2026
This PCEP practice question is part of Courseiva's free Python Institute certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCEP exam.
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