Conditional logic (if-then decisions) in Intro to Computing - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ trace

intermediate

Trace the output of nested if-else statements

Consider the following code snippet. What will be the output after running it?

score = 75
if score >= 90:
    result = "Excellent"
elif score >= 70:
    result = "Good"
else:
    result = "Needs Improvement"
print(result)

Intro to Computing

score = 75
if score >= 90:
    result = "Excellent"
elif score >= 70:
    result = "Good"
else:
    result = "Needs Improvement"
print(result)

A Excellent

B No output (error)

C Needs Improvement

D Good

💡 Hint

Check which condition the score 75 satisfies first.

The score 75 is not >= 90, so the first if is false. The elif checks if score >= 70, which is true, so result is set to "Good". The else block is skipped.

🧠 Conceptual

intermediate

Identify the role of else in conditional statements

Which of the following best describes the role of the else block in an if-then decision structure?

A It runs only if the if condition is false and no elif conditions are true.

B It runs regardless of the if condition.

C It runs only if the if condition is true.

D It runs only if all conditions are true.

💡 Hint

Think about when else executes compared to if and elif.

The else block runs only when none of the previous if or elif conditions are true.

❓ Comparison

advanced

Compare two conditional expressions

Which option correctly shows two equivalent ways to check if a number is between 10 and 20 inclusive?

A 10 <= num <= 20 and num > 10 and num < 20

B 10 <= num <= 20

C num > 10 or num < 20

D num >= 10 and num <= 20 and 10 < num < 20

💡 Hint

Look for the simplest and correct way to check the range.

Option B uses Python's chained comparison which is concise and correct. Other options either add redundant checks or use incorrect logic.

❓ identification

advanced

Identify the error in conditional syntax

What error will this code produce?

if x > 10
    print("Greater")
else:
    print("Smaller or equal")

Intro to Computing

if x > 10
    print("Greater")
else:
    print("Smaller or equal")

A IndentationError due to wrong indentation

B NameError because x is undefined

C SyntaxError due to missing colon after if condition

D No error, prints output correctly

💡 Hint

Check punctuation after the if condition.

Python requires a colon ':' after the if condition. Missing it causes SyntaxError.

🚀 Application

expert

Determine the final value after multiple conditions

Given the code below, what is the final value of status?

value = 15
if value > 20:
    status = "High"
elif value > 10:
    if value % 2 == 0:
        status = "Medium Even"
    else:
        status = "Medium Odd"
else:
    status = "Low"
print(status)

Intro to Computing

value = 15
if value > 20:
    status = "High"
elif value > 10:
    if value % 2 == 0:
        status = "Medium Even"
    else:
        status = "Medium Odd"
else:
    status = "Low"
print(status)

A Medium Odd

B Medium Even

C Low

D High

💡 Hint

Check the value against each condition and the inner if for even or odd.

Value 15 is not > 20, so first if is false. It is > 10, so the elif block runs. Inside, 15 % 2 is 1 (odd), so status is set to "Medium Odd".