Calculate GST Amount (#7694)

* Calculate GST Amount

The program helps to get the net amount after GST is added to it.

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* Update financial/calculating GST.py

Thanks!

Co-authored-by: Christian Clauss <[email protected]>

* Update and rename calculating GST.py to price_plus_tax.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Update price_plus_tax.py

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <[email protected]>

Author: 3 people

financial/price_plus_tax.py

@@ -0,0 +1,18 @@
+"""
+Calculate price plus tax of a good or service given its price and a tax rate.
+"""
+
+
+def price_plus_tax(price: float, tax_rate: float) -> float:
+    """
+    >>> price_plus_tax(100, 0.25)
+    125.0
+    >>> price_plus_tax(125.50, 0.05)
+    131.775
+    """
+    return price * (1 + tax_rate)
+
+
+if __name__ == "__main__":
+    print(f"{price_plus_tax(100, 0.25) = }")
+    print(f"{price_plus_tax(125.50, 0.05) = }")