Get Answers to all your Questions

header-bg qa

Provide Solution For  R.D. Sharma Maths Class 12 Chapter 30 Probaility  Exercise Multiple Choice Questions Question 30 Maths Textbook Solution.

Answers (1)

Answer:(b)

Hint: You must know the rules of finding probability.

Given:P(A)=\frac{3}{10}, P(B)=\frac{2}{5}, P(A \cup B)=\frac{3}{5}

Solution:

\begin{aligned} &P(A \cup B)=\frac{3}{5} \\ &P(A)+P(B)-P(A \cap B)=\frac{3}{5} \\ &\frac{3}{10}+\frac{2}{5}-P(A \cap B)=\frac{3}{5} \\ &P(A \cap B)=\frac{3}{10}+\frac{2}{5}-\frac{3}{5}=\frac{1}{10} \end{aligned}

Now,

\begin{aligned} &P\left(\frac{A}{B}\right)+P\left(\frac{B}{A}\right)=\frac{P(A \cap B)}{P(B)}+\frac{P(A \cap B)}{P(A)} \\\\ &=\frac{\left(\frac{1}{10}\right)}{\left(\frac{2}{5}\right)}+\frac{\left(\frac{1}{10}\right)}{\left(\frac{3}{10}\right)} \\ \end{aligned}

\begin{aligned} \begin{aligned} &P\left(\frac{A}{B}\right)+P\left(\frac{B}{A}\right)=\frac{P(A \cap B)}{P(B)}+\frac{P(A \cap B)}{P(A)} \\\\ &=\frac{\left(\frac{1}{10}\right)}{\left(\frac{2}{5}\right)}+\frac{\left(\frac{1}{10}\right)}{\left(\frac{3}{10}\right)} \\\\ &=\frac{5}{10 \times 2}+\frac{10}{10 \times 3} \\\\ &=\frac{1}{4}+\frac{1}{3} \\\\ &=\frac{4+3}{12}=\frac{7}{12} \end{aligned} \end{aligned}

Posted by

infoexpert21

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads