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About Probability — Class 10 ICSE

Apply probability rules to compound events, conditional probability basics, and tree diagrams. This topic is part of the ICSE Class 10 mathematics syllabus (chapter: Chapter 9). On this page you can practice 60 questions across three difficulty levels — 20 easy, 20 medium, and 20 hard — each with a visual step-by-step solution, plus a timed 10-question mastery test with a live leaderboard. Worked examples and sample questions from the topic are below.

Probability — solved examples for Class 10 ICSE

Example 1easy

A fair coin is tossed once. The probability of getting a head is:
  1. A)00
  2. B)12\frac{1}{2}
  3. C)11
  4. D)14\frac{1}{4}

Step-by-step solution

  1. Sample space:
    S={H,T},  n(S)=2S = \{H, T\},\; n(S) = 2
  2. Favourable outcomes:
    {H},  n(E)=1\{H\},\; n(E) = 1
  3. P(H):
    =12= \frac{1}{2}

Answer: 12\frac{1}{2}

Example 2medium

A card is drawn from a deck of 5252 cards. What is the probability that it is a heart or a king?
  1. A)413\frac{4}{13}
  2. B)1652\frac{16}{52}
  3. C)1752\frac{17}{52}
  4. D)1552\frac{15}{52}

Step-by-step solution

  1. Hearts = 13, Kings = 4, King of Hearts = 1
  2. P(Heart or King):
    =13+4152=1652=413= \frac{13 + 4 - 1}{52} = \frac{16}{52} = \frac{4}{13}

Answer: 413\frac{4}{13}

Example 3hard

A bag contains 55 white and 77 black balls. Two balls are drawn one after the other without replacement. What is the probability that the first is white and the second is black?
  1. A)35132\frac{35}{132}
  2. B)35144\frac{35}{144}
  3. C)512\frac{5}{12}
  4. D)722\frac{7}{22}

Step-by-step solution

  1. P(1st white):
    =512= \frac{5}{12}
  2. P(2nd black | 1st white):
    =711= \frac{7}{11}
  3. P:
    =512×711=35132= \frac{5}{12} \times \frac{7}{11} = \frac{35}{132}

Answer: 35132\frac{35}{132}

Practice questions on Probability

  1. Q1.easy

    A fair die is rolled. What is the probability of getting a number greater than 44?
    1. A)16\frac{1}{6}
    2. B)13\frac{1}{3}
    3. C)23\frac{2}{3}
    4. D)12\frac{1}{2}
    Show answer

    Answer: 13\frac{1}{3}

    Hint: Numbers greater than 4 on a die are 5 and 6.

  2. Q2.easy

    The probability of an impossible event is:
    1. A)00
    2. B)11
    3. C)12\frac{1}{2}
    4. D)1-1
    Show answer

    Answer: 00

    Hint: An impossible event can never happen.

  3. Q3.easy

    A card is drawn at random from a well-shuffled deck of 5252 cards. The probability of getting a king is:
    1. A)152\frac{1}{52}
    2. B)113\frac{1}{13}
    3. C)14\frac{1}{4}
    4. D)413\frac{4}{13}
    Show answer

    Answer: 113\frac{1}{13}

    Hint: There are 4 kings in a deck of 52 cards.

  4. Q4.medium

    Two dice are thrown. What is the probability that the sum is at least 1010?
    1. A)112\frac{1}{12}
    2. B)16\frac{1}{6}
    3. C)536\frac{5}{36}
    4. D)736\frac{7}{36}
    Show answer

    Answer: 16\frac{1}{6}

    Hint: Sum >= 10 means sum is 10, 11, or 12. Count all pairs.

  5. Q5.medium

    A bag contains 55 red, 44 green, and 33 yellow balls. Two balls are drawn one after the other without replacement. What is the probability that both are red?
    1. A)533\frac{5}{33}
    2. B)25144\frac{25}{144}
    3. C)512\frac{5}{12}
    4. D)1066\frac{10}{66}
    Show answer

    Answer: 533\frac{5}{33}

    Hint: Without replacement: P(1st red) x P(2nd red | 1st was red).

  6. Q6.medium

    A number is selected at random from {1,2,3,,20}\{1, 2, 3, \ldots, 20\}. What is the probability that it is a multiple of 33 or 55?
    1. A)920\frac{9}{20}
    2. B)720\frac{7}{20}
    3. C)25\frac{2}{5}
    4. D)1120\frac{11}{20}
    Show answer

    Answer: 920\frac{9}{20}

    Hint: Multiples of 3: {3,6,9,12,15,18}. Multiples of 5: {5,10,15,20}. Watch for overlap at 15.

  7. Q7.hard

    Three cards are drawn from a deck of 5252 cards without replacement. What is the probability that all three are kings?
    1. A)15525\frac{1}{5525}
    2. B)12197\frac{1}{2197}
    3. C)42197\frac{4}{2197}
    4. D)113000\frac{1}{13000}
    Show answer

    Answer: 15525\frac{1}{5525}

    Hint: P = (4/52) × (3/51) × (2/50).

  8. Q8.hard

    A bag has 44 red, 33 blue, and 22 green balls. Three balls are drawn without replacement. What is the probability of getting one ball of each colour?
    1. A)27\frac{2}{7}
    2. B)2484\frac{24}{84}
    3. C)29\frac{2}{9}
    4. D)421\frac{4}{21}
    Show answer

    Answer: 27\frac{2}{7}

    Hint: Use combinations: C(4,1) × C(3,1) × C(2,1) / C(9,3).

  9. Q9.hard

    Two dice are thrown. What is the probability that the product of the two numbers is a perfect square?
    1. A)836\frac{8}{36}
    2. B)1036\frac{10}{36}
    3. C)736\frac{7}{36}
    4. D)936\frac{9}{36}
    Show answer

    Answer: 836\frac{8}{36}

    Hint: List all pairs (a,b) where a×b is a perfect square (1, 4, 9, 16, 25, 36).

These are 9 of the 60 questions available for Probability. Start practicing above to unlock visual solutions, AI coaching, and the topic leaderboard — completely free.