Apply 10% tax to 100
Input
apply_tax(100)
Output
110.0
With TAX_RATE = 0.1, 100 + 100 * 0.1 = 110.0.
Full lesson preview
Define a function that reads a global variable
Use a module-level global variable inside a function to compute a result.
Python practice7 minFunctions & ScopeBeginnerLast updated March 17, 2026
Problem statement
There is a module-level global variable TAX_RATE representing a tax rate (for example 0.10 for 10%). Define a function apply_tax(price) that reads the global TAX_RATE and returns the price after applying tax (price + price * TAX_RATE). Do not reassign TAX_RATE inside the function — only read its value.
Task
Implement a function that reads a global constant (TAX_RATE) and applies it to an input value.
Examples
Input format
A numeric price (int or float). The TAX_RATE global variable is defined in the module.
Output format
A numeric result (float) representing the price after tax.
Constraints
Read the global TAX_RATE variable; do not try to re-declare it inside the function. Support integer and float inputs.
Samples
Sample 1
Input
apply_tax(50.5)
Output
55.55
50.5 + 50.5 * 0.1 = 55.55 (with TAX_RATE = 0.1).