Answer: $18
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Work Shown:
40% = 40/100 = 0.40
40% of 45 = 0.40*45 = 18
The sale price is $18. You save 45-18 = 27 dollars.
Note how 27/45 = 0.60 = 60%, meaning you got a 60% discount. Furthermore, note how 60% + 40% = 100%. So if you get a 60% discount, you still have to pay 40% of the original price.