SAT · Problem Solving & Data Analysis · Scatterplots, tables, and probability
Question sat-q-00165
Medium Multiple choice Calculator OK
The question
A bag contains 7 red marbles and 6 blue marbles. If one marble is drawn at random, what is the probability that it is red?
- 7/13
- 6/13
- 7/6
- 6/7
Show answer & worked solution
Answer: 7/13
Worked solution. Probability = favorable outcomes / total outcomes = 7 / 13.
Why each wrong choice is wrong. Common distractors compute the probability of the other color, or use the wrong color count in the numerator or denominator.
Test-day tactic. Probability is favorable over total. Total includes everything in the sample space, not just the unfavorable outcomes.
About this question type
Items ask you to read a value off a scatterplot, to identify the line of best fit, to compute a probability or conditional probability from a two-way table, or to interpret a relative-frequency statement.
You will see a question shaped like this one on roughly every other official SAT form, typically at a moderate position in the section — solidly within the range that separates a 600-band student from a 700-band student. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.