# 4.10. Exercises: Data and Variables¶

Exercises appear regularly in the book. Just like the concept checks, these exercises will check your understanding of the topics in this chapter. They also provide good practice for the new skills.

Unlike the concept checks, you will need a code editor to complete the exercises. Fortunately, you created a free account on Repl.it as part of the prep work.

Here is the starter repl.it link.

## 4.10.1. The Data¶

Use the information given below about your space shuttle to complete the exercises:

Data Value
Name of the space shuttle Determination
Shuttle Speed (mph) 17,500
Distance to Mars (km) 225,000,000
Distance to the Moon (km) 384,400
Miles per kilometer 0.621

## 4.10.2. The Exercises¶

1. Declare and assign variables

Declare and assign a variable for each item in the list above.

Hint: When declaring and assigning your variables, remember that you will need to use that variable throughout the rest of the exercises. Make sure that you are using the correct data type!

2. Calculate a space mission!

We need to determine how many days it will take to reach Mars.

1. Create and assign a miles to Mars variable. You can get the miles to Mars by multiplying the distance to Mars in kilometers by the miles per kilometer.
2. Next, we need a variable to hold the hours it would take to get to Mars. To get the hours, you need to divide the miles to Mars by the shuttle’s speed.
3. Finally, declare a variable and assign it the value of days to Mars. In order to get the days it will take to reach Mars, you need to divide the hours it will take to reach Mars by 24.
3. Print out the results of your calculations

Using variables from above, print to the screen a sentence that says `"_____ will take ___ days to reach Mars."` Fill in the blanks with the shuttle name and the calculated time.

Click “Run” (in repl.it) and verify that your code works before moving on.

4. Now calculate a trip to the Moon

Repeat the calculations, but this time determine the number of days it would take to travel to the Moon and print to the screen a sentence that says `"_____ will take ___ days to reach the Moon."`.