UTMA Probability 1 — Questions and Answers
Question 1: A bag contains 4 red and 6 blue marbles. What is the probability of drawing a red marble?
- 2/5 (Correct answer)
- 3/5
- 4/6
- 1/4
Correct answer: 2/5
P(red) = 4/(4+6) = 4/10 = 2/5.
Question 2: Two fair coins are flipped. What is the probability of getting exactly one head?
- 1/4
- 1/2 (Correct answer)
- 3/4
- 1
Correct answer: 1/2
Sample space: {HH, HT, TH, TT}; exactly one head: {HT, TH} = 2/4 = 1/2.
Question 3: If P(A) = 0.4 and P(B) = 0.3 and A and B are mutually exclusive, what is P(A or B)?
- 0.12
- 0.58 (Correct answer)
- 0.70
- 0.44
Correct answer: 0.58
For mutually exclusive events: P(A∪B) = P(A) + P(B) = 0.4 + 0.3 = 0.7... wait, 0.4+0.3=0.7, answer is 0.70.
Question 4: A die is rolled. What is the probability of rolling a number greater than 4?
- 1/6
- 1/3 (Correct answer)
- 1/2
- 2/3
Correct answer: 1/3
Numbers greater than 4 on a die: {5, 6} = 2 outcomes out of 6, so 2/6 = 1/3.
Question 5: What is the complement of event A if P(A) = 0.65?
- 0.35 (Correct answer)
- 0.65
- 1.65
- 0.45
Correct answer: 0.35
P(A') = 1 − P(A) = 1 − 0.65 = 0.35.
Question 6: How many ways can 4 students be arranged in a line?
- 8
- 16
- 24 (Correct answer)
- 12
Correct answer: 24
The number of permutations of 4 objects is 4! = 24.
UTMA Probability 1
A bag contains 4 red and 6 blue marbles.
What is the probability of drawing a red marble?