This page contains a list of typos or errors from my books. If you think you've found an error, please let me know through the contact page. The edits will be incorporated in future editions.

#### SAT Math: The Advanced Guide and Workbook

**Chapter 3 Exponential vs. Linear Growth, #3 (pg. 26)**: The answer explanation on page 260 has a typo. The rate should be \(1 - 0.06 = 0.94\).

**Chapter 23 Trigonometry, #12 (pg. 207)**: The answer explanation on page 310 has a typo. In quadrant III, sine and cosine are both **negative** (not positive).

**Chapter 25 Probability, #10 (pg. 223)**: The first sentence of the question should read *"A manufacturer uses two assembly lines to produce refrigerators."*

The following errors are fixed for books purchased after May 6, 2018. Also note that the math book was updated slightly with new material on that date.

**Chapter 2 Percent (pg. 16)**: The Part 2 Solution should read "Car Speeding Violations / **Total Violations**", not "Total Parking Violations".

**Chapter 2 Percent (pg. 17)**: In Example 4, Jonas is a guy, so the question should read "His initial deposit..."

**Chapter 3 Exponential vs. Linear Growth (pg. 26)**: The final amount \(A\) would be \(A = 100 - 10t\)

**Chapter 3 Exponential vs. Linear Growth, #1 (pg. 27)**: The question should read, *If the initial population of rats was 20 and grew to 25 after the first year, ...*

**Chapter 4 Proportion, Example 2 (pg. 31)**: Answers A and B are duplicated. Answer B should read *Decreases by 10%*.

**Chapter 8 More Equation Solving Strategies, #4 (pg. 65)**: The answer explanation has a typo. The -4 should turn into a +4 when it's brought over to the other side. The last step is correct, as well as the answer.

**Chapter 15 Quadratics (pg. 131)**: The ** minimum** value of \(f(x)\) is \(-6.125\).

**Chapter 22 Trigonometry, #9 (pg. 203)**: The equation is missing a parentheses: \(\sin 58 = \sin(5m - 12)\)

**Chapter 23 Reading Data, #15 (pg. 212)**: The question should read, *According to the graph, by how many hours is Greg's glucose recovery time after lunch greater than his glucose recovery time after breakfast?* The answer explanation should be adjusted accordingly.

**Chapter 25 Statistics I, #13 (pg. 232)**: This question needs to be revised as none of the answer choices are correct. The correct answer should be *The mean number of films shown in each class is greater in School B, but the median is the same in both schools*.

**Chapter 27 Volume (pg. 248)**: The volume of a sphere is \(\dfrac{4}{3}\pi r^3\).

The following errors are fixed for books purchased after Sep. 8, 2016.

**Chapter 20 Triangles, #30 (pg. 186)**: The equilateral triangle is **AED**, not BEC.

**Chapter 22 Trigonometry (pg. 200)**: Step 2 for finding the value of a trig function without a calculator is incorrect. Step 2 should be "Find the reference angle".

Thus, the examples were done incorrectly. In example 1, the reference angle is \(30^\circ\). So \(\sin 330^\circ = -\sin 30^\circ = -\dfrac{1}{2}\)

**Chapter 22 Trigonometry, #6 (pg. 202)**: \(AB = 5\), as shown in the diagram, NOT 4 as the question states.

#### SAT Writing: Advanced Guide and Workbook

**Chapter 6 Subject Verb Agreement, Exercise 3, #3 (pg. 26)**: This question needs to be revised as the answer is unclear. "A variety" can take a singular or plural verb depending on the context and the emphasis. For this question, the answer could be either singular or plural. The good news is that the SAT won't test you on this distinction.

**Chapter 18 Word Choice, Example 6 (pg. 108)**: The "to" in the question sentence should not be underlined.

The following errors are fixed in the 2nd edition (July 23, 2018).

**Chapter 14 Commas, Dashes, & Colons, #5 (pg. 87)**: Answers A and C are duplicated. Answer C shouldn't have a comma at the end.

**Chapter 14 Commas, Dashes, & Colons, #10 (pg. 94)**: The correct answer is A, not B.

**Chapter 15 Apostrophes, #3 (pg. 98)**: Answers A and D are duplicated. This will be revised in a future edition.

**Chapter 15 Apostrophes, #4 (pg. 98)**: Answers C and D are duplicated. This will be revised in a future edition.

**Chapter 21 Placement, Exercise 1, #12 (pg. 163)**: A and D are essentially the same answer, so both are correct. This will be revised in a future edition.

**Chapter 23 Comparatives vs. Superlatives, #7 (pg. 178)**: The word "the" is duplicated.

#### SAT Math: 10 Practice Tests

**Practice Test 1, Section 3, #2**: The answer is correct but here's the correct explanation: \(\dfrac{\dfrac{1}{x}}{x + 3} = \dfrac{1}{x}\div (x + 3) = \dfrac{1}{x}\times\dfrac{1}{x + 3} = \dfrac{1}{x(x + 3)}\)

**Practice Test 1, Section 3, #3**: The answer is correct but here's the correct explanation: The equation is satisfied only when \(x = 2, y = 3\), and \(z = -4\). So, \(x + y + z = 2 + 3 + (-4) = \boxed{1}\).

**Practice Test 2, Section 3, #19**: The question should read *the expression above is equivalent to \(\dfrac{k}{x(x - 3)^2}\)* (NOT \(\dfrac{k}{(x - 3)^2}\))

The following errors are fixed for books purchased after May 6, 2018. Also note that the math practice test book was updated significantly with new material on that date. Many questions were replaced with ones more aligned with The College Board's gradual tweaks to the exam.

**Practice Test 1, Section 3, #4**: The answer listed is correct but the explanation refers to another problem. For this question, \(x = 2, y = 3, z = -4\) so \(x + y + z = \boxed{1}\)

**Practice Test 1, Section 4, #14**: The answer listed is correct but the explanation should say "tripling per hour," not "doubling per hour."

**Practice Test 3, Section 4, #14**: This question needs to be revised because none of the answers are correct. Since a box can only hold 30 lbs, it can only hold \(\dfrac{30}{1.4\times 2.2} = 9.74\) books, rounding down to \(9\) books per box. Therefore, \(800\) books would require \(\dfrac{800}{9} = 88.88\) boxes, rounding up to \(89\) boxes.

**Practice Test 4, Section 4, #28**: The question should read \(AB = BC\)

**Practice Test 5, Section 4, #9**: Answers A and D are essentially the same (they're both correct). This will be revised in the next edition.

**Practice Test 7, Section 3, #9**: All answer choices should have \(t\) in the denominator, not \(b\).

**Practice Test 8, Section 4, #33**: The question should read \(\sin 24^\circ = \cos(3k + 6)^\circ\) (Note the parentheses).

**Practice Test 8, Section 4, #38**: The question should be clearer: What is the velocity of the block, in meters per second, immediately after the spring is uncoiled *from its currently displaced position of 0.05 meters*?

**Practice Test 9, Section 4, #33**: The question should read "what is the *minimum* possible value of \(x\)?" The answer is 14, but the answer explanation should be interpreted accordingly.

*Special thanks to Aung for most of these edits!*

#### ACT English

The following errors are fixed for books purchased after May 25, 2017.

**Chapter 4 Prepositional Phrases, #6 (pg. 19)**: "Since the hypothesis" is a prepositional phrase that should also be crossed out in the answer.

**Chapter 15 Commas, #15 (pg. 84)**: The correct answer is B, not A.

**Chapter 18 Word Choice, Exercise 2**

1. C

2. A

3. B

4. A

5. B

6. B

7. A

8. D

9. C

10. B

11. D

12. C

13. A

14. B

15. C

16. B

17. D

**Chapter 22 Placement, Exercise 1, #12 (pg. 137)**: A and D are essentially the same answer, so both are correct. This will be revised in a future edition.

**Chapter 22 Placement, Exercise 3, #3 (pg. 146)**: The answer explanation on page 215 has an error. The sentence "It also transitions smoothly into paragraph 3," is wrong. Replace that sentence with "Paragraph 5 provides an intentional contrast to the vibrant picture portrayed in paragraph 4, so paragraph 5 should follow paragraph 4."

**Chapter 23 Relevance & Purpose, Exercise 2, #9 (pg. 159)**: This question is poorly constructed and can be ignored. The answer sort of depends on the student's answer to #8 and is therefore unclear.

**Chapter 24 Dashes & Colons, #18 (pg. 168)**: The correct answer is B, not C.

**Chapter 34 Practice Test 3, #61 (pg. 273)**: The correct answer is A, not C.

*Special thanks to Tamim and Sofia for most of these edits!*

#### ACT Math: Advanced Guide and Workbook

**Chapter 1 Absolute Value, #7 (pg. 8)**: The correct answer is C, not E.

**Chapter 6 Properties of Numbers, Example 6 (pg. 35)**: The correct answer should be \(\dfrac{3}{25} = 12\%\), since only 3 numbers (10, 32, and 54) are even.