JEE PYQ: Probability Question 3
Question 3 - 2021 (17 Mar Shift 1)
Two dices are rolled. If both dices have six faces numbered 1, 2, 3, 5, 7 and 11, then the probability that the sum of the numbers on the top faces is less than or equal to 8 is:
(1) $\frac{4}{9}$
(2) $\frac{17}{36}$
(3) $\frac{5}{12}$
(4) $\frac{1}{2}$
Show Answer
Answer: (2)
Solution
Total outcomes $= 36$. Count pairs $(a,b)$ with $a + b \leq 8$: $(1,1),(1,2),(1,3),(1,5),(1,7)$, $(2,1),(2,2),(2,3),(2,5)$, $(3,1),(3,2),(3,3),(3,5)$, $(5,1),(5,2),(5,3)$, $(7,1)$ = 17. $P = \frac{17}{36}$.
BETA
