GED Mathematical Reasoning TestQuantitative Problem Solving with Rational NumbersHard
A store offers a promotion where customers receive an additional 1/5 off the discounted price of an item. If an item originally cost $100 and was first discounted by 20%, what is the final price after the additional promotion?
- A$64
- B$60
- C$80
- D$75
Show answer & explanationAnswer & explanation
Correct answer: A. $64
First discount: $100 * 20% = $20. Price after first discount: $100 - $20 = $80. Second discount (1/5 off the discounted price): $80 * (1/5) = $16. Final price: $80 - $16 = $64.
Why the other options are wrong
- B. This could be if 1/5 was taken off the original price, resulting in a total 40% off.
- C. This is the price after only the first discount, not the final price.
- D. This is an incorrect calculation, possibly if 1/4 was taken off or other error.
Sequential Fractional and Percentage Discounts
Sequential discounts are applied one after another, where each subsequent discount is calculated on the *already discounted* price, not the original price. Fractions and percentages can be mixed in these calculations.
- Apply discounts one at a time, in order.
- Each discount is based on the current price, not the original.
- Convert percentages to decimals and fractions to decimals for easier calculation.
Memory trick: Discount, then discount the new price again.