Exercise 2: In some countries, a vehicle’s fuel efficiency is measured in miles per gallon. In other

Exercise 2: In some countries, a vehicle’s fuel efficiency is measured in miles per gallon. In other countries, the efficiency is measured in litres per 100 km. For example, 32 miles per Imperial gallon is equivalent to approximately 8.83 litres per 100 km. You’re going to write Python statements that convert miles per gallon to litres per 100 km. One Imperial gallon is equal to approximately 4.54609 litres. One mile is equal to approximately 1.60934 km. Hint: the most difficult part of this exercise is the math, not the Python. I recommend that you first treat this as a math problem; that is,

»Exercise 2: In some countries, a vehicle’s fuel efficiency is measured in miles per gallon. In other countries, the efficiency is measured in litres per 100 km. For example, 32 miles per Imperial gallon is equivalent to approximately 8.83 litres per 100 km. You’re going to write Python statements that convert miles per gallon to litres per 100 km. One Imperial gallon is equal to approximately 4.54609 litres. One mile is equal to approximately 1.60934 km. Hint: the most difficult part of this exercise is the math, not the Python. I recommend that you first treat this as a math problem; that is, derive a formula for converting miles per gallon to litres per 100 km, using the conversion factors listed in the previous paragraph. Verify that the units in the conversion factors cancel out properly. Converting a correct formula to Python is the easy part. Delete the code in PyTutor’s editor, then: 1. Type one assignment statement that creates a new variable named mpg and binds it to the value 32 (which represents 32 miles per gallon). 2. Type two assignment statements that create new variables named LITRES_PER_GALLON and KMS_PER_MILE and bind them to the values 4.54609 and 1.60934, respectively. (Note that the names of Python variables that have values that are supposed to remain constant are, by convention, usually written entirely in uppercase.) 3. Type one assignment statement that converts the mileage bound to mpg to the equivalent fuel consumption, measured in litres per 100 km. This value should be bound to a variable named fuel_consumption. Click the Visualize Execution button. Execute the code, one statement at a time, and observe the memory diagram as the code is executed, step-by-step. Verify that your code converts 32 mpg into 8.83 litres per 100 km. If necessary, correct your code and retest it. When your code is correct, copy/paste the four assignment statements from PyTutor into lab2.txt. Record your answers to these questions in lab2.txt, then save the file. (a) What is the name of the first variable that appears in the diagram? What is the type and value of the object that it refers to? (b) What is the name of the second variable that appears in the diagram? What is the type and value of the object that it refers to? (c) What is the name of the third variable that appears in the diagram? What is the type and value of the object that it refers to? (d) What is the name of the fourth variable that appears in the diagram? What is the type and value of the object that it refers to? Questions :

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