SAT Percentages Question
For an online trivia game, 490 points are awarded for a correct answer if a question is answered in less than 5 seconds from the time the question is asked. Each 5 seconds after the question is asked, the number of points awarded for a correct answer decreases by 20% of the number of points awarded for a correct answer in the previous 5 seconds. Which function gives the number of points awarded for a correct answer x seconds from the time the question is asked, where x is a multiple of 5?
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The trap here
Why +10% then −10% isn't 0% on SAT Math — The classic SAT percent-change trap: successive percentage changes multiply, they don't add.