Quiz Solution: Evaluate composed boolean expressions

altitude < 1000 and speed > 100

altitude < 1000 is False , so we don't even need to check the second condition - the whole expression is False .

(propulsion == "Jet" or propulsion == "Turboprop") and speed < 300 and altitude > 20000

propulsion == "Jet" is False , and propulsion == "Turboprop" is False , so the whole expression inside the parentheses is False . It is combined with the other expressions with and , so we don't even need to check these - the whole expression must be False because the first part is False .

not (speed > 400 and propulsion == "Propeller")

To work this one out, we need to look at the inside of the parentheses first, then apply not to that. speed > 400 is False, and because we are using and this makes the whole of the expression inside the parentheses False . Applying not reverses this, so this expression is True .

(altitude > 500 and speed > 100) or not propulsion == "Propeller"

Let's start by looking inside the parentheses. altitude > 500 is True , and speed is greater than 100 , so the expression inside the parenthesis is True . Whatever the value of the other expression, because they are connected by or , the whole expression will evaluate to True .

Quiz Solution: Using Truth Values of Objects

points = 174

points = 174  # use this input when submitting your answer

# set prize to default value of None
prize = None

# use the value of points to assign prize to the correct prize name
if points <= 50:
    prize = "wooden rabbit"
elif 151 <= points <= 180:
    prize = "wafer-thin mint"
elif points >= 181:
    prize = "penguin"

# use the truth value of prize to assign result to the correct message
if prize:
    result = "Congratulations! You won a {}!".format(prize)
else:
    result = "Oh dear, no prize this time."

print(result)

Output

Congratulations! You won a wafer-thin mint!

We first set prize to None and then update it only if falls into a bracket that results in winning a prize. This is accomplished in the first if statement. We then use the truth value of prize to assign result to a message based on whether a prize was won.

Remember when prize = "penguin" , or any other non-empty string, then the if prize condition is True!