Percentages and Percent Change · Sub-skill drill
Percent Increase and Decrease
Percent change is the change divided by the original value, multiplied by 100. The most common error is dividing by the new value instead of the original. A second common error is treating an increase from 50 to 80 as a 30 percent increase (it is actually 60 percent, since 30 is 60 percent of 50). Memorize the formula and always identify the original value before dividing. Wrong-answer choices on these questions are designed to catch each of these specific misreads.
How this sub-skill is tested on the SAT
Percent change is the change divided by the original value, multiplied by 100. The most common error is dividing by the new value instead of the original. A second common error is treating an increase from 50 to 80 as a 30 percent increase (it is actually 60 percent, since 30 is 60 percent of 50). Memorize the formula and always identify the original value before dividing. Wrong-answer choices on these questions are designed to catch each of these specific misreads.
This sub-skill sits inside the broader Percentages and Percent Change topic, which is part of the College Board's Problem Solving & Data Analysis content domain. Problem Solving and Data Analysis is where the SAT pretends to be the real world. Every question in this domain is wrapped in context: a recipe, a survey, a clinical trial, a lab measurement, a marketing report. The math itself is rarely harder than middle-school arithmetic — ratios, proportions, percentages, unit conversions, means, medians, scatter plots, two-way tables, and basic probability. What trips students up is the reading. The College Board has spent two decades calibrating these prompts to reward students who slow down on the setup and punish students who rush to compute. ScoreRe
Practice questions in this drill set
Below are 6 practice questions targeting this exact sub-skill, ordered from easier to harder. Each question is tagged with its target score band so you can focus on questions that match the band you are working out of. Worked solutions are open by default — read each one even if you got the question right, because the way the solution is structured often reveals a faster path than the one you used.
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A jacket originally priced at $415 is marked down by 20%. What is the sale price?
- A 332.00
- B 337.00
- C 415.00
- D 327.00
Worked solution
Answer: A — 332.00
Discount = 415 × (20/100) = 83.00. Sale price = 415 - 83.00 = $332.00.
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A stock priced at $690 rises by 35% in one week, then falls by 35% the next week. What is the final price?
- A 605.48
- B 690.00
- C 610.48
- D 600.48
Worked solution
Answer: A — 605.48
After the first week: 690 × (1 + 35/100). After the second week: multiply by (1 - 35/100). The result is 690 × (1 - 1225/10000) = $605.48. Note: this is less than the original, even though the percentages are equal — a common SAT trap.
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A laptop originally priced at $495 is increased by 15%. What is the new price?
- A 564.25
- B 574.25
- C 495.00
- D 569.25
Worked solution
Answer: D — 569.25
Increase = 495 × (15/100) = 74.25. New price = 495 + 74.25 = $569.25.
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A jacket originally priced at $825 is marked down by 15%. What is the sale price?
- A 696.25
- B 825.00
- C 706.25
- D 701.25
Worked solution
Answer: D — 701.25
Discount = 825 × (15/100) = 123.75. Sale price = 825 - 123.75 = $701.25.
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A stock priced at $425 rises by 25% in one week, then falls by 25% the next week. What is the final price?
- A 403.44
- B 393.44
- C 398.44
- D 425.00
Worked solution
Answer: C — 398.44
After the first week: 425 × (1 + 25/100). After the second week: multiply by (1 - 25/100). The result is 425 × (1 - 625/10000) = $398.44. Note: this is less than the original, even though the percentages are equal — a common SAT trap.
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A laptop originally priced at $920 is increased by 20%. What is the new price?
- A 1,104.00
- B 1,109.00
- C 1,099.00
- D 920.00
Worked solution
Answer: A — 1,104.00
Increase = 920 × (20/100) = 184.00. New price = 920 + 184.00 = $1,104.00.
Why this band assignment matters
Every question in this drill is tagged with a target score band — 400–500, 500–600, 600–700, or 700–800 — based on its difficulty and the patterns the College Board uses for questions at each level. If you are aiming to break out of a 580 plateau, the 600–700 questions in this drill are your highest-leverage practice. If you are chasing 750+, the 700–800 questions here are the ones that separate the top 10% of test takers from everyone else.
Use the band tags to filter your work. If you can confidently solve every 400–500 and 500–600 question without notes, move to the 600–700 set. If those land cleanly, the 700–800 set is your final boss. The worked solutions in this drill are written so that even the hardest questions become learnable patterns once you have seen the structure of the solve a few times.