Jee Main 2024 29 01 2024 Shift 2 - Question1
Question 1
Given set $={1,2,3, \ldots, 50}$
One number is selected randomly from set. Find probability that number is multiple of 4 or 6 or 7 .
(1) $\frac{21}{50}$
(2) $\frac{18}{50}$
(3) $\frac{8}{25}$
(4) $\frac{21}{25}$
Show Answer
Answer: (1)
Solution:
Take $P(A)=$ Probability that number is multiple of 4 $P(B)=$ Probability that number is multiple of 6 $P(C)=$ Probability that number is multiple of 7
$P(A)=\frac{12}{50}, P(B)=\frac{8}{50}, P(C)=\frac{7}{50}$
$P(A \cap B)=\frac{4}{50}$ (Multiple of 12)
$P(B \cap C)=\frac{1}{50}$ (Multiple of 42)
$P(A \cap C)=\frac{1}{50}$ (Multiple of 28)
$P(A \cap B \cap C)=0$ (Multiple of 84)
$P(A \cup B \cup C)=P(A)+P(B)+P(C)-P(A \cap B)-$
$P(B \cap C)-P(A \cap C)+P(A \cap B \cap C)$
$=\frac{12}{50}+\frac{8}{50}+\frac{7}{50}-\frac{4}{50}-\frac{1}{50}+0$
$=\frac{21}{50}$





