Question

The probability that the $13$th day of a randomly chosen month is a Friday, is

• A. $\frac{1}{70}$
• B. $\frac{1}{84}$
• C. $\frac{1}{12}$
• D. $\frac{1}{77}$

Answer 1

Answer: (B)

$\frac{1}{84}$

Probability of selecting a month out of 12 months $=\frac{1}{12}$

Probability that the 13th day of the selected month is friday $=\frac{1}{7}$

$\therefore$ Probability that the 13th day of randomly chosen month $=\frac{1}{12}\times \frac{1}{7}$

$=\frac{1}{84}$