Problem-Solving and Data AnalysisHardProbability of two draws without replacement
Problem-Solving and Data Analysis practice question
A bag contains 4 red marbles and 6 blue marbles. Two marbles are drawn at random without replacement. What is the probability that both are blue?
Answer: 1/3
P(first blue) = 6/10, then P(second blue) = 5/9. Product: 30/90 = 1/3.
Common wrong answers
- If you answered 9/25
- 9/25 is (6/10)² for drawing with replacement.
- If you answered 3/5
- 3/5 is the probability of one blue draw.
- If you answered 1/6
- 1/6 is (6/10)(5/9) halved by mistake.
More Problem-Solving and Data Analysis questions
- Hard
The mean of five numbers is 12. If four of them are 8, 10, 14, and 16, what is the fifth number? - Hard
In a survey of 50 people, 30 like coffee, 20 like tea, and 8 like both. How many like neither? - Hard
A car travels at 60 mph for 2 hours, then 40 mph for 3 hours. What is its average speed for the whole trip? - Hard
Which statement correctly compares the standard deviations of the two sets? - Hard
Which statement best interprets the slope of the line of best fit? - Hard
How many milliliters of the 40% acid solution must the chemist add?
Not affiliated with the College Board. SAT is a trademark of the College Board.