Probability — Class 12 Maths Solution

exemplar objective MCQ NCERT,Exemp,Q.82,Page.283
Question

Two dice are thrown. If it is known that the sum of numbers on the dice was less than 6, the probability of getting a sum 3, is

  • (a) $\frac{1}{{18}}$
  • (b) $\frac{5}{{18}}$
  • (c) $\frac{1}{5}$ ✓ Correct
  • (d) $\frac{2}{5}$
Step-by-step Solution
Correct answer: option (c)

Let ${E_1} =$ Event that the sum of numbers on the dice was less than 6 and ${E_2} =$ Event that the sum of numbers on the dice is 3

$\therefore$ ${E_1} = \{ (1,4),(4,1),(2,3),(3,2),(2,2),(1,3),(3,1),(1,2),(2,1),(1,1)\}$

$\Rightarrow$ $n\left( {{E_1}} \right) = 10$

and ${E_2} = \{ (1,2),(2,1)\} \Rightarrow n\left( {{E_2}} \right) = 2$

$\therefore$ Required probability $= \frac{2}{{10}} = \frac{1}{5}$

NCERT & Exemplar solution for CBSE Class 12 Mathematics, Probability. Curated by Sachin Sharma. Free for all students.