Q$1$: Explain why functions are useful in programming.

Q$2$: Write a short Python script without functions that calculates both the perimeter and area of a rectangle. Then, refactor it to use functions for these calculations $.($Use void Functions$)$

Q$3$: Write a void function called print$\_$hello that prints the message "Hello, World!" five times.

Q$4$: Write a function named display$\_$user$\_$info that accepts a user's name and age as parameters and prints a message in the format: "Name: $[$name$],$ Age: $[$age$]".$ The function should not return any values.

Q$5$: Write a function named calculate$\_$total$\_$cost that takes two parameters: price and tax$\_$rate. The function should print the total cost after adding tax. Call this function with the arguments $100$ and $7\mathrm{.}5,$ and explain the difference between parameters and arguments in this example.