GMAT Multi-Source Reasoning: map the tabs, route each question, time the set

Multi-Source Reasoning spreads one situation across several tabs and then asks a set of questions about it. The format tests whether you can find the right tab fast, combine a rule in one tab with figures in another, and refuse to assume what no tab says. This guide gives you a three-part method for every set: map the tabs, route each question, and time the set.

What the format looks like

A Multi-Source Reasoning set gives you several tabs of material, such as a memo, an email, a table, or a chart, and a set of questions that draw on them. Some questions ask you to mark each of several statements yes or no, or true or false; others use standard multiple choice. The questions in a set share the same tabs, so a careful first reading pays off across the whole set.

Two section rules shape your plan. Data Insights gives you 20 questions in 45 minutes, an average of 2 minutes 15 seconds each, along with an on-screen calculator. And a question with several statements earns credit only when you judge every statement correctly.

Part 1: Map the tabs

Spend about a minute on the tabs before you answer anything. Open each tab and write one line about it in your notes: what kind of source it is, what it holds, and anything that limits it. Sort what you find into three kinds of content:

• Rules: requirements, policies, thresholds, and exceptions. Write down each threshold and whether the rule says at least, more than, or below.
• Figures: tables and charts. Write down the column headings, the units, and the period the numbers cover.
• Views: opinions, plans, forecasts, and claims by named people. Label them as views, because a plan or a forecast tells you nothing about what actually happened.

Do not try to memorize the tabs. The map exists to tell you where to look, and a good one fits in three short lines.

Part 2: Route each question

Read each question before you reread any tab, and decide which tab or tabs it needs. The wording usually tells you:

• A number, a total, a percent, or a column heading sends you to the table or chart.
• A word such as qualifies, allowed, must, or eligible sends you to the rule.
• A person’s name, a plan, or a forecast sends you to the email or message.
• A question about whether something meets a standard needs two tabs: the rule from one and the figures from another.

Write the route next to the question number, such as “memo + table”, before you search. Routing keeps you from rereading every tab for every question, and it flags the questions that need two sources, where a one-tab answer goes wrong.

Part 3: Judge from the sources only

For each yes-or-no statement, ask whether the tabs state it or force it. If no tab states it and no combination of tabs forces it, the sources do not support it, however reasonable it sounds. Your map should already show you the three limits that decide most close calls: the period the figures cover, the exact threshold in each rule, and the difference between a plan and a result.

Example: the training grant

Example: A set shows three tabs. Tab 1, a policy memo, says an office qualifies for a training grant only if its staff grew by at least 10 percent from January 2025 to January 2026 and its 2026 travel spending stayed below $50,000. Tab 2, a table, lists each office’s staff in January 2025 and January 2026 and its 2026 travel spending: North went from 40 staff to 43 and spent $38,000; South went from 50 to 56 and spent $52,000; East went from 30 to 33 and spent $41,500. Tab 3, an email from the North office manager, says the office hired two more people in February 2026, which puts its growth well above 10 percent.

The question asks you to mark Yes or No for each office: does the office qualify for the grant?

Map: Tab 1 holds a rule with two conditions, growth of at least 10 percent and travel spending below $50,000. Tab 2 holds the staff counts for January 2025 and January 2026 and the 2026 travel spending. Tab 3 holds one manager’s claim. Route: the question asks whether each office meets a standard, so it needs the memo and the table, and the email needs a check because it names North.

North grew from 40 to 43, a gain of 3 on a base of 40, or 7.5 percent, so it fails the growth test. The February hires in the email come after the memo’s January 2026 cutoff, so they change nothing: No. South grew by 6 on a base of 50, or 12 percent, but it spent $52,000, which does not fall below $50,000: No. East grew by 3 on a base of 30, exactly 10 percent, which meets the at-least threshold, and it spent $41,500: Yes. The answers run No, No, Yes, and you earn credit only if you get all three right.

The example packs in three traps that the method catches: a view that sounds decisive (the email), a second condition that a table-only reading misses (South’s travel spending), and a boundary case (East’s growth of exactly 10 percent).

Timing per set

Budget about one minute for the map and 1.5 to 2 minutes for each question. A set of three questions then takes 5.5 to 7 minutes. At the section average of 2 minutes 15 seconds per question, three questions earn you 6 minutes 45 seconds, so a mapped set keeps you close to pace. The map does the saving: the first question carries the reading, and each later question reuses it.

Set a hard stop near 3 minutes per question. If a question passes it, pick the answer that your routed tabs support most strongly, bookmark the question, and move on. Question Review & Edit lets you change up to three answers per section with any time you have left at the end.

Mistakes to avoid

• Answering from one tab when the question needs two. A statement that looks true from the table can break the memo’s rule.
• Treating a plan, a forecast, or an opinion as a fact.
• Ignoring the period the figures cover. A number from the wrong year answers a different question.
• Rounding a threshold. At least 10 percent includes exactly 10 percent, and below $50,000 excludes $50,000.
• Rereading every tab for every question. Route first, then read only the tab the route names.

GMAX holds Multi-Source Reasoning questions with an explanation after every answer and an on-screen calculator, as on the exam. The free plan gives you five practice questions and one rated match a day, so you can practice the map and the routing every day.