For a banking application allowing withdrawals of 20, 100, or 500 dollars, how many equivalence partitions need to be tested?

To determine the number of equivalence partitions for testing the banking application that allows withdrawals of specific amounts (20, 100, or 500 dollars), it is essential to identify valid and invalid input scenarios.

In this case, valid inputs are the specified withdrawal amounts of 20, 100, and 500 dollars. These represent individual equivalence partitions, as each one behaves differently in the system when submitted. So, there are three distinct valid equivalence partitions corresponding to the amounts that can be withdrawn.

Besides these, there are also invalid partitions. Since withdrawals outside of the predefined amounts are not allowed, any amount that is not 20, 100, or 500 dollars will form another partition. This means you can consider:

• Any amount less than 20 (e.g., 0, 10, 15)
• Any amount greater than 500 (e.g., 600, 1000)
• Any non-numeric input (like negative numbers or text)

This leads to the identification of four equivalence partitions to be tested:

1. A valid partition (20 dollars)
2. A valid partition (100 dollars)
3. A valid partition (500 dollars)
4. An invalid partition (all other