RD Sharma Class 12 Exercise 30.2 Probability Solutions Maths-Download PDF Online

RD Sharma Class 12 Exercise 30.2 Probability Solutions Maths-Download PDF Online

Updated on 25 Jan 2022, 04:01 PM IST

The RD Sharma class 12 solution Probability exercise 30.2 is a tricky chapter to be solved by any student. The RD Sharma class 12th exercise 30.2 starts with the explanation of the basic concepts of the chapter and then moves on to introducing the challenging questions to prepare the students in every way out to score high in the maths exam. The Class 12 RD Sharma chapter 30 exercise 30.2 solution consists of a total of 16 questions to give a brief of the essential concepts of the chapter that are mentioned below-

This Story also Contains

  1. RD Sharma Class 12 Solutions Chapter30 Probability - Other Exercise
  2. Probability Excercise: 30.2
  3. RD Sharma Chapter-wise Solutions

The axiomatic approach of Probability

  • The classical theory of Probability

  • Conditional Probability

  • Permutation and Combination

  • With replacement and without replacement type questions

  • Union and Intersection

  • Question based on Cards and balls

  • RD Sharma Class 12 Solutions Chapter30 Probability - Other Exercise

    Probability Excercise: 30.2

    Probability exercise 30.2 question 1

    Answer:
    $\frac{1}{221}$
    Hint:
    Use formula of probability, where
    $P(A\cap B)=P(A)\times P\left ( \frac{B}{A} \right )$
    Given, a pack of 52 cards.
    Solution: So Let, A = A king in first trial
    B = A king in second trial.
    Now, Total cards are 52.
    $\begin{aligned} &P(A)=\frac{ \text { No. of elements of A }}{\text { Total no. of elements }}\\ &=\frac{4}{52}=\frac{1}{13} \end{aligned}$
    Now
    $\begin{aligned} &P\left ( \frac{B}{A} \right )=\text { A consecutive king without replacement after first trial.}\\ &=\frac{\text { No. of kings in cards }}{\text { Total number of cards after excluding one king }}\\ &=\frac{3}{51} \qquad \text { (After trail cards will be and there will be kings) }\\ &=\frac{1}{17} \end{aligned}$
    Now,
    $\begin{aligned} &\text { Required Probability }=P(A\cap B)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{1}{13}\times \frac{1}{17}\\ &=\frac{1}{221} \end{aligned}$

    Probability exercise 30.2 question 2

    Answer:
    $\frac{1}{270725}$
    Hint:
    $\text { Probability }=\frac{\text { No. of favourable outcomes }}{ \text { Total no. of outcomes }}$
    Solution:
    Let, A = An ace in the first draw.
    B = An ace in the 2nd draw.
    C = An ace in the 3rd draw.
    D = An ace in the 4th draw.
    $\begin{aligned} &\text { Probability of A }=\frac{4}{25}\\ &=\frac{1}{13}\\ &P\left ( \frac{B}{A} \right )=\frac{3}{51}=\frac{1}{17}\\ &P\left ( \frac{C}{A\cap B} \right )=\frac{2}{50}=\frac{1}{25}\\ &P\left ( \frac{D}{A\cap B\cap C} \right )=\frac{1}{49} \end{aligned}$
    $\begin{aligned} &\text { Required Probability }=P\left ( A\cap B\cap C\cap D \right )\\ &=P(A)\times P\left ( \frac{B}{A} \right )\times P\left ( \frac{C}{A\cap B} \right )\times P\left ( \frac{D}{A\cap B\cap C} \right )\\ &=\frac{1}{13}\times \frac{1}{17}\times \frac{1}{25}\times \frac{1}{49}\\ &=\frac{1}{270725} \end{aligned}$

    Probability exercise 30.2 question 3

    Answer:
    $\frac{7}{22}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Let, A = White ball in first draw.
    B = White ball in second draw.
    Solution:
    Now,
    $\begin{aligned} &P(A)=\frac{7}{12}\\ &P\left ( \frac{B}{A} \right )=\frac{6}{11}\\ &\text { Required Probability }=P(A\cap B)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{7}{12}\times \frac{6}{11}\\ &=\frac{42}{132}\\ &=\frac{7}{22} \end{aligned}$

    Probability exercise 30.2 question 4

    Answer:
    $\frac{11}{50}$
    Hint:
    Consider events for tickets and use probability formula
    Given, 12 even number between 1 to 25
    Solution:
    Let,
    A = An even number ticket in the first draw
    B = An even number ticket in the second draw
    Now,
    $\begin{aligned} &P(A)=\frac{12}{25}\\ &P\left (\frac{B}{A} \right )=\frac{11}{25}\\ &\text { Required Probability }=P(A\cap B)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{15}{25}\times \frac{11}{24}\\ &=\frac{11}{50} \end{aligned}$

    Probability exercise 30.2 question 5

    Answer:
    $\frac{11}{850}$
    Hint:
    To find probability that each time it is card of a spade, calculate the events and take ratio with total events
    Let, A = An ace in the 1st draw
    B = An ace in the 2nd draw
    C = Getting an ace in the 3rd draw.
    Now,
    $\begin{aligned} &P(A)=\frac{13}{52}=\frac{1}{4}\\ &P\left ( \frac{B}{A} \right )=\frac{12}{51}=\frac{4}{17}\\ &P\left ( \frac{C}{B\cap A} \right )=\frac{11}{50}\\ &\text { Required Probability }=P(A\cap B\cap C)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\times \frac{C}{B\cap A}\\ &=\frac{1}{4}\times \frac{4}{17}\times \frac{11}{50}\\ &=\frac{11}{850} \end{aligned}$


    Probability exercise 30.2 question 6(i)

    Answer:
    $\frac{1}{221}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given events
    Let A=A king in 1st draw
    B= A king in 2nd draw
    Solution:
    $\begin{aligned} &P(A)=\frac{4}{52}=\frac{1}{13}\\ &P\left ( \frac{B}{A} \right )=\frac{3}{51}=\frac{1}{17}\\ &\text{ Required Probability }=P(A\cap B)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{1}{13}\times \frac{1}{17}\\ &=\frac{1}{221} \end{aligned}$

    Probability exercise 30.2 question 6(ii)

    Answer:
    $\frac{4}{663}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given Events
    Let A= A king in 1st draw
    B= An ace in the 2nd draw
    Solution:
    $\begin{aligned} &P(A)=\frac{4}{52}=\frac{1}{13}\\ &P\left ( \frac{B}{A} \right )=\frac{4}{51}\\ &\text { Required Probability }=P(A\cap B)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{1}{13}\times \frac{4}{51}\\ &=\frac{4}{663} \end{aligned}$

    Probability exercise 30.2 question 6(iii)

    Answer:
    $\frac{25}{204}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given, events as follows
    Let C=A heart in the 1st throw
    D=A red card in the 2nd throw
    Now,
    $\begin{aligned} &P(C)=\frac{13}{52}=\frac{1}{4}\\ &P\left ( \frac{C}{D} \right )=\frac{25}{51}\\ &\text { Required Probability }=P(C\cap D)\\ &=P(C)\times P\left ( \frac{C}{D} \right )\\ &=\frac{1}{4}\times \frac{25}{51}\\ &=\frac{25}{204} \end{aligned}$

    Probability exercise 30.2 question 7

    Answer:
    $\frac{5}{19}$
    Hint:
    Just take events and apply probability.
    Given,
    A=An even number in the 1st draw
    B= An odd number in the 2nd draw
    Now,
    $\begin{aligned} &P(A)=\frac{10}{20}=\frac{1}{2}\\ &P\left ( \frac{B}{A} \right )=\frac{10}{19}\\ &\text { Required Probability }=P(A\cap B)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{1}{2}\times \frac{10}{19}\\ &=\frac{5}{19} \end{aligned}$

    Probability exercise 30.2 question 8

    Answer:
    $\begin{aligned} &\frac{15}{22} \end{aligned}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given events
    A=A white or red ball in the 1st draw.
    B=A white or red ball in the 2nd draw.
    Now,
    $\begin{aligned} &P(A)=\frac{7}{12}\\ &P\left ( \frac{B}{A} \right )=\frac{6}{11}\\ &P(A\cap B)=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{7}{12}\times \frac{6}{11}\\ &=\frac{7}{22}\\ &\text { Required Probability }=1-P(A\cap B)\\ &=1-\frac{7}{22}\\ &=\frac{15}{22} \end{aligned}$

    Probability exercise 30.2 question 9

    Answer:
    $\frac{8}{65}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given, events
    Let A=A white or black ball in the 1st draw
    B=A white or black ball in the 2nd draw
    C=A white or black ball in the 3rd draw
    Now,
    $\begin{aligned} &P(A)=\frac{8}{15}\\ &P\left ( \frac{B}{A} \right )=\frac{7}{14}=\frac{1}{2}\\ &P\left ( \frac{C}{B\cap A} \right )=\frac{6}{13}\\ &\text { Required Probability }=P(A\cap B\cap C)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\times P\left ( \frac{C}{B\cap A} \right )\\ &=\frac{8}{15}\times \frac{1}{2}\times \frac{6}{13}\\ &=\frac{8}{65} \end{aligned}$

    Probability exercise 30.2 question 10

    Answer:
    $\frac{13}{204}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given, A=A heart in the 1st draw
    B=A diamond in the 2nd draw
    $\begin{aligned} &P(A)=\frac{13}{52}=\frac{1}{4}\\ &P\left ( \frac{B}{A} \right )=\frac{13}{51}\\ &\text { Required Probability }=P(A\cap B)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{1}{4}\times \frac{13}{51}\\ &=\frac{13}{204} \end{aligned}$

    Probability exercise 30.2 question 11

    Answer:
    $\frac{3}{7}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given, events
    A=A black ball in the 1st draw
    B=A black ball in the 2nd draw
    Now,
    $\begin{aligned} &P(A)=\frac{10}{15}=\frac{2}{3}\\ &P\left ( \frac{B}{A} \right )=\frac{9}{14}\\ &\text { Required Probability }=P(A\cap B)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\\ &=\frac{2}{3}\times \frac{9}{14}\\ &=\frac{3}{7} \end{aligned}$

    Probability exercise 30.2 question 12

    Answer:
    $\begin{aligned} &\frac{2}{5525} \end{aligned}$
    Hint:
    $\begin{aligned} &\text { Probability }=P(A\cap B\cap C)=P(A)\times P\left ( \frac{B}{A} \right )\times P\left ( \frac{C}{B\cap A} \right ) \end{aligned}$
    Given, events
    A=A king in the 1st draw
    B=A king in the 2nd draw
    $\begin{aligned} &P(A)=\frac{4}{52}=\frac{1}{13}\\ &P\left ( \frac{B}{A} \right )=\frac{3}{51}=\frac{1}{17}\\ &P\left ( \frac{C}{B\cap A} \right )=\frac{4}{50}=\frac{2}{25}\\ &\text { Required Probability }=P(A\cap B\cap C)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\times P\left ( \frac{C}{B\cap A} \right )\\ &=\frac{1}{13}\times \frac{1}{17}\times \frac{2}{25}\\ &=\frac{2}{5525} \end{aligned}$

    Probability exercise 30.2 question 13

    Answer:
    $\begin{aligned} &\frac{44}{91} \end{aligned}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given,
    A=A good orange in the 1st draw
    B=A good orange in the 2nd draw
    C=A good orange in the 3rd draw
    Now,
    $\begin{aligned} &P(A)=\frac{12}{15}=\frac{4}{5}\\ &P\left ( \frac{B}{A} \right )=\frac{11}{14}\\ &P\left ( \frac{C}{B\cap A} \right )=\frac{10}{13}\\ &\text { Required Probability }=P(A\cap B\cap C)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\times P\left ( \frac{C}{B\cap A} \right )\\ &=\frac{4}{5}\times \frac{11}{14}\times \frac{10}{13}\\ &=\frac{440}{910}=\frac{44}{91} \end{aligned}$

    Probability exercise 30.2 question 14

    Answer:
    $\begin{aligned} &\frac{1}{24} \end{aligned}$
    Hint:
    $\begin{aligned} &\text { Probability }=\frac{\text { No. of event favourable outcomes }}{ \text { Total no. of outcomes }} \end{aligned}$
    Given,
    A=A white ball in the 1st draw
    B=A black ball in the 2nd draw
    C=A red ball in the 3rd draw
    $\begin{aligned} &P(A)=\frac{4}{16}=\frac{1}{4}\\ &P\left ( \frac{B}{A} \right )=\frac{7}{15}\\ &P\left ( \frac{C}{B\cap A} \right )=\frac{5}{14}\\ &\text { Required Probability }=P(A\cap B\cap C)\\ &=P(A)\times P\left ( \frac{B}{A} \right )\times P\left ( \frac{C}{B\cap A} \right )\\ &=\frac{1}{4}\times \frac{7}{15}\times \frac{5}{14}\\ &=\frac{1}{24} \end{aligned}$


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