Conditional Probability — Quick Reference Cheatsheet
A focused companion to the main Conditional Probability topic page on SAT Math.
SAT Math Problem-Solving & Data Analysis One-page reference
This is a one-page reference for Conditional Probability on the SAT math section. Apply P(A | B) = P(A and B)/P(B) using table or tree-diagram reasoning. Use it as a printable cheatsheet before test day, or as a refresher right before you attempt the worked questions on the main Conditional Probability topic page.
What this topic is
A Conditional Probability question tests your ability to extract data from a table, chart, or word problem and apply ratio, percentage, statistics, or probability reasoning. Reading carefully is more than half the battle.
Core formulas you must memorise
- Mean = sum / count
- Percent change = (new − old) / old × 100%
- Probability = favourable / total
- Conditional: P(A | B) = P(A ∩ B) / P(B)
- Unit rate: divide both quantities by the same denominator
If any of these formulas are not yet automatic, drill them via the Problem-Solving & Data Analysis formula sheet. Memorisation is fastest when you write each formula out by hand five times in a row, then quiz yourself the next morning.
How to spot this question type on the test
SAT questions on Conditional Probability typically present in one of three ways: as a pure symbolic problem ("solve for x"), wrapped in a word problem (a real-world scenario you must translate), or hidden inside a longer multi-step question where Conditional Probability is just the first or last step. Train yourself to recognise the signature — a particular word, equation form, or diagram — and you will halve your reading time.
The 30-second decision
Underline the statistic the question is asking for (mean, median, mode, range, percent change). Half of all PSDA wrong answers come from confusing two statistics with similar names.
If you have 60 seconds before the question
Glance at the answer choices first. If they are widely spaced, estimate; if they are close, you must be exact. Sketch any diagram involved. Identify which of the formulas above applies. Then attempt — and if you cannot finish in 90 seconds, mark and move on. There is no penalty for guessing on either the SAT or the ACT, so always bubble in.
Drill set
Re-attempt the six worked Conditional Probability questions with this cheatsheet open. Then close it and re-attempt them from memory. If you can solve all six without peeking, this topic is locked in.
Related study material
For broader test-prep tactics, see our Conditional Probability strategy guide. For category-wide context, browse all Problem-Solving & Data Analysis topics. For score-targeted study plans, see the score-band guides.