Answer: $59.25
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Step-by-step explanation:
There are two approaches
Method 1
25% of 79 = 0.25*79 = 19.75
Mary saves $19.75 and the price before tax is 79 - 19.75 = 59.25
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Method 2
She saves 25% so she must pay the remaining 75%
75% of 79 = 0.75*79 = 59.25
This is a slight shortcut, and it's very useful when it comes to chaining multiple discounts together.