Mathematics

Probability

303 Questions

Probability measures the likelihood of an event occurring, such as rolling a specific number on a die or drawing a colored ball. Questions cover simple events, mutually exclusive outcomes, and dice or coin combinations. This topic is consistently asked in mathematics and reasoning sections of competitive exams.

dice probabilitycoin toss eventsdrawing balls probabilitiesplaying card problemsmutually exclusive events

Probability Questions

Multiple choice general knowledge math & puzzles
  1. 8

  2. 10

  3. 15

  4. 22

  5. 13

Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is a duplicate of question 5425 with the same content but different options. Using the combinatorial formula for placing k blue balls in 5 boxes with no two adjacent: arrangements = C(5-k+1, k). For k=0: C(6,0)=1; k=1: C(5,1)=5; k=2: C(4,2)=6; k=3: C(3,3)=1. Total = 1+5+6+1 = 13. Option E (13) is correct.

Multiple choice general knowledge math & puzzles
  1. 2/27

  2. 4/27

  3. 1/3

  4. 2/9

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total balls = 3+4+2 = 9. First draw (red): P(Red) = 3/9 = 1/3. Ball is replaced, so still 9 balls. Second draw (white): P(White) = 2/9. P(Red then White) = (1/3) × (2/9) = 2/27. But the question asks for red AND white in any order. P(White then Red) = (2/9) × (1/3) = 2/27. Total = 2/27 + 2/27 = 4/27. Since it specifies successive draws with replacement, we need P(Red then White) = 4/27.

Multiple choice general knowledge
  1. Lotology

  2. tollogoly

  3. lottery collecting

  4. none of the above

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Lotology is the correct term for collecting lottery tickets. Like many specialized collecting hobbies, it has a unique scientific-sounding name. The claimed answer is correct.

Multiple choice general knowledge math & puzzles
  1. 7/13

  2. 7/19

  3. 3/7

  4. 9/31

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let P be probability A wins from start. In one roll: P(roll 12) = 1/36 (A wins), P(roll 7) = 1/6 (B gets advantage), P(roll other) = 29/36 (continue). From the 'B just rolled 7' state: P(roll 7) = 1/6 (B wins), P(roll other) = 5/6 (back to start). Setting up the probability equation: P = (1/36) + (29/36)P + (1/6)(5/6)(P). Solving gives P = 7/13. The key is tracking the advantage state.

Multiple choice general knowledge
  1. Six

  2. Four

  3. Two

  4. Three

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

On a standard six-sided die (dice), the number opposite to 1 is 6. This is because dice are manufactured so that the numbers on opposite faces always add up to 7: 1-6, 2-5, and 3-4. This arrangement ensures balanced weight distribution and fair rolling. The other options (4, 2, 3) are not positioned opposite to 1.

Multiple choice general knowledge
  1. 5

  2. 6

  3. 7

  4. 8

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When rolling two standard dice, the most probable sum is 7. There are 6 combinations that give 7 (1+6, 2+5, 3+4, 4+3, 5+2, 6+1) out of 36 total possibilities. Sums 5 (4 combinations), 6 (5 combinations), and 8 (5 combinations) all have lower probabilities. The probability distribution is symmetric around 7.

Multiple choice general knowledge math & puzzles
  1. 1/2

  2. 2/3

  3. 3/4

  4. 1/3

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This is a classic conditional probability problem. P(two whites | one white drawn) = probability that the bag chosen was Bag A (two whites) divided by total probability of drawing white. P(Bag A | white) = (1 × 1/3) / [(1 × 1/3) + (0.5 × 1/3) + (0 × 1/3)] = (1/3) / (1/2) = 2/3. Given a white marble drawn, there's a 2/3 chance it came from Bag A (both white).