Question

A number is chosen at random from among the 1st 50 natural numbers. The probability that the number chosen is either a prime number or a multiple of 5 is

• A. $\frac{12}{25}$
• B. $\frac{1}{2}$
• C. $\frac{14}{25}$
• D. $\frac{1}{4}$

Answer 1

Answer: (A)

$\frac{12}{25}$

P(either prime no. or multiple of 5) $=$ P(prime no.)$+$P(multiple 5)$-$ P(both prime & multiple of 5)
$=(15+10-1)/50=12/25$