The-probability-that-a-leap-year-selected-at-random-contains-either-53-Sundays-or-53-Mondays-is-

Question Number 8803 by desniati@rocketmail.com last updated on 28/Oct/16

The probability that a leap year selected

at random contains either 53 Sundays or

53 Mondays, is

Answered by myintkhaing last updated on 02/Nov/16

n u m b e r o f d a y s i n l e a p y e a r = 366

n u m b e r o f d a y s i n 52 w e e k s = 364

t h e s e x t r a 2 d a y s m a y b e

(S u n M o n) (M o n T u e) (T u e W e d)

(W e d T h u) (T h u F r i) (F r i S a t) (S a t S u n)

P (53^{r d} S u n d a y s) = P (A) = \frac{2}{7}

P (53^{r d} M o n d a y s) = P (B) = \frac{2}{7}

P (A B) = \frac{1}{7}

P (A o r B) = P (A) + P (B) - P (A B)

= \frac{2}{7} + \frac{2}{7} - \frac{1}{7} = \frac{3}{7}