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

You have three bags, each containing two marbles. Bag A contains two white marbles, Bag B contains two black marbles, and Bag C contains one white marble and one black marble. You pick a random bag and take out one marble. It is a white marble. What is the probability that the remaining marble from the same bag is also white?

  1. 1/3

  2. 2/3

  3. 1/2

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Classic conditional probability (Bayesian reasoning). You drew a white marble. This could come from Bag A (2 white) or Bag C (1 white, 1 black), not Bag B (2 black). Given white marble, probability you picked Bag A is 2/3 (2 white marbles in A vs 1 in C). If from Bag A, remaining marble is white. So answer = 2/3. This is not 1/3 (that's the prior probability of picking Bag A), not 1/2 (ignoring the evidence).

Multiple choice technology programming languages

How do you generate random numbers within a given limit with actionscript?

  1. Math.round(Math.random() * (high - low)) + low

  2. Math.round(Math.random())

  3. Math.round(Math.random())+ low

  4. None of the baove
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Math.random() returns a value in the range [0, 1). Multiplying it by the range size (high - low), rounding the result using Math.round(), and shifting it by adding low correctly generates a random integer in the closed interval [low, high]. Other choices fail to scale or shift the output correctly.

Multiple choice

An unbalanced dice (with 6 faces, numbered from 1 to 6) is thrown. The probability that the face value is odd is 90% of the probability that the face value is even. The probability of getting any even numbered face is the same. If the probability that the face is even given that it is greater than 3 is 0.75, which one of the following options is closest to the probability that the face value exceeds 3?

  1. 0.453

  2. 0.468

  3. 0.485

  4. 0.492
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice

A fair dice is rolled twice. The probability that an odd number will follow an even number is
  1. $\dfrac{1}{2}$
  2. $\frac{1}{6}$
  3. $\frac{1}{3}$
  4. $\frac{1}{4}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Probability of coming odd number is $\frac{1}{2}$ and the probability of coming even number is $\frac{1}{2}$. Both the events are independent to each other, thus probability of coming odd number after as even number is $\frac{1}{2} \times \frac{1}{2} = \frac{1}{4}$

Multiple choice

A fair dice is tossed two times. The probability that the second toss results in a value that is higher than the first toss is

  1. 2/36

  2. 2/6

  3. 5/12

  4. 1/2
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$\text{Total outcome are 36 out of which favorable outcomes are:} //// (1, 2), (1, 3), (1, 4), (1, 5), (1, 6), (2, 3), (2, 4), (2, 5), (2, 6); \\ (3, 4), (3, 5), (3, 6), (4, 5), (4, 6), (5, 6) \text{which are 15.} \ \text{Thus} \hspace{1cm} P(E) = \frac{\text{No. of favourable outcomes}}{\text{No. of total outcomes}}=\frac{15}{36} = \frac{5}{12}$