Working with variables, data types, and operators in PHP Mocktest

In PHP, variables are declared using the $ symbol followed by the variable name and assigned a value using the = operator. Hence, the correct way to declare a variable named "name" with the value "John" is $name = "John";.

Variable names in PHP must start with a letter or underscore, followed by any combination of letters, numbers, or underscores. Hyphens are not allowed in variable names. Therefore, $my_var is a valid variable name, while $my-var and $my var are not.

The code calculates the sum of $x and $y using the addition operator (+) and then prints the result using the echo statement. Therefore, the output will be 15, as $x + $y evaluates to 10 + 5, which equals 15.

In PHP, variables can hold different types of data. In the given code, the variable $age is assigned an integer value 25. Therefore, the data type of $age is Integer, which represents whole numbers without decimals.

Floating-point numbers in PHP are assigned using the decimal point. Therefore, the correct way to assign a floating-point number 10.99 to a variable $price is $price = 10.99;. Assigning it as a string or an integer will result in a different data type.

In PHP, the period (.) operator is used for concatenation of strings. It joins two string values together to form a single string. For example, "Hello" . " " . "World" will result in "Hello World".

In PHP, double quotes (") allow variable interpolation, meaning that variables within the string will be replaced with their values. Therefore, the output of the code will be Hello, John!, as the variable $name will be replaced with its value "John" when the string is echoed.

Arrays in PHP are declared using the array() construct. Therefore, the correct way to declare an array $colors with values "Red", "Green", and "Blue" is $colors = array("Red", "Green", "Blue");. The other options are incorrect syntax for declaring arrays in PHP.

The code initializes $x with the value 5 and then adds 3 to it using the += operator. Therefore, after execution, $x will have the value 8, as 5 + 3 equals 8.

The === operator in PHP is the identity operator, which checks if two values are equal and of the same data type. It compares both the value and the data type of the operands. Therefore, === is used to compare whether two values are equal and of the same data type.