MDTP Probability 2 — Questions and Answers
Question 1: A jar has 4 red and 6 blue marbles. One marble is drawn without replacement. What is the probability both draws are red?
- 2/15 (Correct answer)
- 4/25
- 16/100
- 2/5
Correct answer: 2/15
P(red then red) = (4/10) × (3/9) = 12/90 = 2/15.
Question 2: Which value cannot be a probability?
- 0
- 0.5
- 1
- 1.5 (Correct answer)
Correct answer: 1.5
Probabilities must be between 0 and 1 inclusive; 1.5 exceeds this range.
Question 3: How many different 3-digit combinations can be formed from the digits 1–9 if repetition is allowed?
- 27
- 84
- 504
- 729 (Correct answer)
Correct answer: 729
With repetition allowed, there are 9 × 9 × 9 = 9³ = 729 combinations.
Question 4: P(A) = 0.6. What is P(A')?
- 0.6
- 0.4 (Correct answer)
- 1.6
- 0.36
Correct answer: 0.4
The complement rule states P(A') = 1 - P(A) = 1 - 0.6 = 0.4.
Question 5: In how many ways can a committee of 2 be chosen from a group of 6 people?
- 12
- 15 (Correct answer)
- 30
- 36
Correct answer: 15
Order doesn't matter, so C(6,2) = 6!/(2!4!) = 15.
Question 6: A student guesses randomly on a 4-choice multiple-choice question. What is the probability of guessing wrong?
- 1/4
- 1/2
- 3/4 (Correct answer)
- 1
Correct answer: 3/4
P(correct) = 1/4, so P(wrong) = 1 - 1/4 = 3/4.
MDTP Probability 2
A jar has 4 red and 6 blue marbles.
One marble is drawn without replacement.
What is the probability both draws are red?