GRE Quant · Chapter Test
Probability — 25-Question Test
A fresh, mixed-difficulty set drawn from the whole chapter — questions you haven't been asked before. Auto-graded with full solutions; your result is saved to your dashboard.
Building your 25-question test…
Formula Reference Sheet
This chapter
Core probability
| Basic probability | P(E) = favourable outcomes / total equally-likely outcomes |
|---|---|
| Range of a probability | 0 ≤ P(E) ≤ 1 |
| Complement | P(not E) = 1 − P(E) |
| Independent "and" | P(A and B) = P(A) × P(B) |
Combining events
| General "or" | P(A or B) = P(A) + P(B) − P(A and B) |
|---|---|
| Mutually exclusive "or" | P(A or B) = P(A) + P(B) (no overlap) |
| Dependent "and" | P(A then B) = P(A) × P(B given A) |
| "At least one" | P(at least one) = 1 − P(none) |
GRE reference
🖩 Graphing Calculator