A box holds 5 green and 5 yellow balls. Two balls are taken one after the other without replacement. What is the probability that both are green?
Answer and explanation
Correct answer: A.
- Step 1: First ball green: 5/10. Then 4 green balls remain among 9.
- Step 2: Multiply: 5/10 x 4/9 = 2/9.
Answer
.
Practise more Mathematics: Probability and Counting.
Free questions with an explanation for every one, and full timed FUVEST (University of São Paulo Entrance Exam) mock tests.
More Mathematics: Probability and Counting questions
- A bag has 2 red and 8 blue marbles. One marble is drawn at random. What is the probability it is red?
- In a class, 33 students play football, 31 play volleyball and 9 play both. 10 play neither. How many students are in the class?
- A fair die is rolled 3 times. What is the probability of getting at least one six?
- Two fair dice are rolled. What is the probability that the sum is 9?
- Two fair dice are rolled. What is the probability that the sum is 4?
- A fair die is rolled 4 times. What is the probability of getting at least one six?