SAT Percentages and Units

Percentages and units cover percent change, percent of a total, and conversion between units. Successive percent changes do not add — a rise then a fall is applied to different bases, which is exactly the trap this skill names.

Practise this skill freeHow the SAT is structured
MathProblem-Solving and Data Analysis39 questions
The trap on this skill

Applying tax to the original price or combining percent changes by simple subtraction.

How this skill behaves

What 39 questions on it look like

87% of these questions can appear in the harder second module. On a section-adaptive test that matters: this is a skill that keeps mattering after a strong first module, not one you leave behind.

Not one question in this skill is rated hard. What makes it cost marks is speed and carelessness, not difficulty.

medium87%
easy13%

Difficulty mix across the 39 questions in this skill.

From the bank

Three real percentages and units questions

Each one explains the credited answer and why every other option fails.

Problem-Solving and Data Analysis · medium

A store entry in ticketbooth daily gate mapping invoice shows a $135 item with a 20% markdown. After the markdown, 7% tax is added. How many dollars is the final price?

  1. A108.00
  2. B115.56correct
  3. C144.45
  4. D117.45
Why B is correct — and why the others are not

After the discount, the price is 135(1 - 20/100). Then applying tax gives 135(1 - 20/100)(1 + 7/100) = 115.56. This matches the evidence or condition involving Percentages and units. A final check is recomputing the change rather than relying on an endpoint.

A. This value results from applying tax to the original price or combining percent changes by simple subtraction

C. This value results from applying tax to the original price or combining percent changes by simple subtraction

D. This value results from applying tax to the original price or combining percent changes by simple subtraction

Problem-Solving and Data Analysis · easy

For a purchase recorded in mailroom lower podium folding setup note, the listed price is $230. A 10% discount is applied first, followed by a 5% tax on the reduced price. What is the final cost?

  1. A207.00
  2. B241.50
  3. C218.50
  4. D217.35correct
Why D is correct — and why the others are not

After the discount, the price is 230(1 - 10/100). Then applying tax gives 230(1 - 10/100)(1 + 5/100) = 217.35. The key support is the way the item treats Percentages and units. A final check is substitution back into the original condition.

A. This value results from applying tax to the original price or combining percent changes by simple subtraction

B. This value results from applying tax to the original price or combining percent changes by simple subtraction

C. This value results from applying tax to the original price or combining percent changes by simple subtraction

Problem-Solving and Data Analysis · medium

A store entry in observatory primary box counting batch card shows a $195 item with a 10% markdown. After the markdown, 6% tax is added. How many dollars is the final price?

  1. A175.50
  2. B206.70
  3. C187.20
  4. D186.03correct
Why D is correct — and why the others are not

After the discount, the price is 195(1 - 10/100). Then applying tax gives 195(1 - 10/100)(1 + 6/100) = 186.03. The key support is the way the item treats Percentages and units. A final check is checking the requested variable before recording the answer.

A. This value results from applying tax to the original price or combining percent changes by simple subtraction

B. This value results from applying tax to the original price or combining percent changes by simple subtraction

C. This value results from applying tax to the original price or combining percent changes by simple subtraction

39 questions on this skill, free to start.

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FAQ

Percentages and Units questions

How do I calculate percent change?

Difference divided by the ORIGINAL value, then times 100. Using the new value as the base is the common error.

Can I add two percent changes together?

No. Apply them in order — each acts on the amount produced by the one before it.
Last reviewed 2026-08-28. Format and scoring facts sourced to College Board. Question counts describe the PrepScore bank, not the exam.
Same domain
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Practise percentages and units until the trap stops working.

Real Digital SAT questions, the reasoning on every option, and a mistake bank that only clears when you get it right.

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