Read the table first
Before the question exists, spend eight seconds on the figure itself.
Four things, in this order. (1) What is one row? (2) What does each column measure, and in what unit? (3) Which direction is “more”? (4) Is anything already a percentage, or is everything a raw count?
Column three is the one students skip. A column headed Days to first corrosion rewards a larger number; a column headed Days to failure under load might too; a column headed Time to dry does not always. The claim in the passage tells you which direction counts as better — read the claim, then reread the header.
Bảng của SAT không bao giờ khó về tính toán. Cái khó nằm ở chỗ câu văn phía trên nói về một đại lượng còn bảng lại cho hai ba đại lượng, và học sinh lấy nhầm cột. Chỉ tay vào đúng cột trước khi đọc phương án là thao tác rẻ nhất trong cả phần Đọc.
The correct choice has two jobs
Job 1 — read the figure correctly. Right row, right column, right unit.
Job 2 — do what the sentence needs. Establish a trend, draw a contrast, complete a
comparison, or give the example the sentence promised.
Almost every wrong answer on this question type does Job 1 perfectly and skips Job 2. That is what makes them hard: nothing in them is false.
| Finish | Roughness index | Drying time (min) |
|---|---|---|
| Polished | 0.4 | 18 |
| Satin | 2.1 | 26 |
| Matte | 6.8 | 41 |
| Textured | 15.0 | 63 |
- the polished tile, the smoothest of the four, dried in 18 minutes.
- the textured tile took 63 minutes to dry.
- drying time rose from 18 minutes to 63 minutes as the roughness index rose from 0.4 to 15.0.
- the satin tile was rougher than the polished tile.
All four read the table correctly. (A) and (B) each report one cell, and a single cell cannot show that drying time depends on roughness. (D) compares roughness to roughness and never mentions drying at all. Only (C) puts the two variables side by side across the whole range. Answer (C).
Phương án nêu đúng một ô của bảng luôn đúng và luôn vô dụng. Một điểm dữ liệu không chứng minh được quan hệ. Muốn ủng hộ một xu hướng thì phương án phải nhắc hai giá trị của biến nguyên nhân và hai giá trị của biến kết quả — thiếu một trong bốn con số đó là chưa đủ.
A comparison can also do Job 2 by holding one variable still while another moves — the shape a claim about which variable matters demands.
| Lake | Mean depth (m) | Shoreline habitat types | Fish species |
|---|---|---|---|
| 1 | 4 | 2 | 9 |
| 2 | 22 | 2 | 10 |
| 3 | 6 | 5 | 21 |
| 4 | 31 | 3 | 13 |
| 5 | 9 | 6 | 24 |
| 6 | 38 | 3 | 12 |
Which choice most effectively uses data from the table to support the team's argument?
- Lake 6, the deepest at 38 metres, had 12 fish species.
- Lakes 1 and 2 each had two shoreline habitat types and 9 and 10 species, although their mean depths differ by 18 metres.
- Lake 5 had the most fish species, 24.
- Lake 3 had five shoreline habitat types and a mean depth of 6 metres.
The argument needs depth held irrelevant while habitat does the work. (B) fixes habitat at two types, varies depth by 18 metres, and species barely move — which is precisely the pattern the claim predicts. (A), (C) and (D) each report one row without comparing anything. Answer (B).
Counts versus shares
When two groups differ in size, raw counts answer a different question from proportions. The test uses this every time it can.
| District | Households | Tonnes recycled | Tonnes to landfill |
|---|---|---|---|
| North (Scheme A) | 44,000 | 12,000 | 28,000 |
| South (Scheme B) | 16,000 | 6,000 | 9,000 |
Which choice most effectively uses data from the table to support the analyst's claim?
- North recycled 12,000 tonnes, twice as much as South's 6,000 tonnes.
- South recycled 40 percent of its household waste, compared with 30 percent in North.
- North sent 28,000 tonnes to landfill while South sent 9,000 tonnes.
- South has fewer households than North.
North's waste totals $12{,}000+28{,}000=40{,}000$ tonnes, of which $12{,}000$, or $30\%$, was recycled. South's totals $6{,}000+9{,}000=15{,}000$ tonnes, of which $6{,}000$, or $40\%$, was recycled. (A) and (C) are accurate and point the wrong way: North is simply a bigger district, so its totals are bigger under any scheme. (D) is true and is the very reason raw totals cannot settle the question. Answer (B).
Quy tắc: khi hai nhóm có quy mô khác nhau, mọi câu “nhóm nào làm tốt hơn” đều phải trả lời bằng tỉ lệ, không bằng tổng. Ngược lại, khi câu hỏi là “nhóm nào đóng góp nhiều hơn vào tổng thể” thì lại phải dùng số tuyệt đối. Đọc kỹ nhận định để biết mẫu số nằm ở đâu.
Graphs: axes, direction, crossing point
For a graph the same discipline applies to the axes. Two features carry most of the questions: the point where a curve changes slope, and the point where two curves cross.
Which choice most effectively uses data from the graph to support the student's claim?
- The concentration reached 11.5 milligrams per litre at 4 p.m.
- The concentration rose through the daylight hours, from 5.0 at 6 a.m.\ to 11.5 at 4 p.m., and fell overnight to 4.2 at 4 a.m.
- The concentration at 4 a.m., 4.2 milligrams per litre, was the lowest value recorded.
- The concentration never fell below 4.0 milligrams per litre.
The claim ties the rise to daylight, so the supporting statement must pair light with rise and dark with fall. (A) and (C) each name one endpoint. (D) is a fact about the range that would be true whatever drove the pattern. Answer (B).
Completing a sentence that has already promised something
Many items are not questions but blanks. The words before the blank fix what must come next: although promises a contrast, for instance promises one case, in fact promises something stronger than what preceded.
| Tin (%) | Tensile strength (MPa) | Days to first corrosion |
|---|---|---|
| 2 | 310 | 12 |
| 5 | 285 | 27 |
| 9 | 240 | 58 |
| 14 | 195 | 96 |
- had the highest tensile strength of the four alloys tested.
- resisted corrosion for 96 days, the longest of the four, while showing the lowest tensile strength, 195 MPa.
- had a tensile strength of 240 MPa.
- showed the first signs of corrosion after 12 days.
The sentence names one alloy — the one with the highest tin content, the 14 percent row — and the opening Although has promised both halves of a trade-off. (C) and (D) read from the 9 percent and 2 percent rows. (A) reverses the table. Answer (B).
Chữ nối trước chỗ trống là mệnh lệnh, không phải trang trí. Although bắt buộc phần điền vào phải chứa một sự đánh đổi — được cái này mất cái kia. For instance bắt buộc phải nêu đúng một trường hợp. In fact đòi một điều mạnh hơn câu vừa nói. Đọc bảng xong mà quên đọc chữ nối là chọn nhầm một phương án đúng số nhưng sai nhiệm vụ.
| Town | Registered boats | Tonnes landed |
|---|---|---|
| Aber | 62 | 940 |
| Brent | 41 | 1,380 |
| Cole | 88 | 1,120 |
| Dane | 25 | 610 |
- Cole's 88 boats landed 1,120 tonnes, less than the 1,380 tonnes landed by Brent's 41 boats.
- Aber landed 940 tonnes with a fleet of 62 boats.
- Dane had the smallest fleet and landed the least fish.
- Cole landed 1,380 tonnes, more than any other town.
(D) takes the right number from the wrong row — the classic misreading, and the one that feels safest because the figure really is in the table. (C) is read correctly and illustrates the opposite of the sentence: there, fleet size and tonnage move together. (B) reports a row without a comparison. Answer (A).
Bốn kiểu hỏng, xếp theo tần suất: (1) đúng số nhưng chỉ một ô; (2) đúng số, đúng so sánh, nhưng so sánh sai đại lượng mà nhận định đang bàn; (3) lấy nhầm hàng hoặc nhầm cột; (4) dùng số tuyệt đối cho một câu hỏi về tỉ lệ. Kiểu thứ hai là kiểu hay bị chọn nhất, vì nó trông giống hệt đáp án đúng.