Question

Gita, Sita, Rita & Anitha are friends. What is the probability that in a non-leap year (i)All will have same birthday (ii)Birthday falls in October (iii)Birthday fall on 10th day of month (iv) Birthday fall in January or February?

Answer 1

Answer:

Step-by-step explanation:

(1) All will have same birthday

Probability of Anita's birthday = 365365

Now Sita,Gita and Rita have their birthdays fixed .

So each of them has the probability 1365

Thus required probability = (365365×1365×1365×1365)=(13653)

(2) Their birthdays fall in the month of october.

As the month of october consists of 31 days.

In this case ,each of the four has the probability (31365)

Thus required probability = (31365×31365×31365×31365) = (31365)4

(3)Their birthdays fall on the 10th day of the month

So in every month there comes the date 10th

So number of these days = number of months = 12

So in this case , each of the four has the probability 12365

Thus required probability = (12365×12365×12365×12365) = (12365)4

(4)Their birthdays fall in January and February

As January consists of 31 days and February consists of 28 days (non-leap year)

So total number of days in January and February = (31+28) = 59 days

So in this case, each of the four has the probability 59365

Thus required probability = (59365×59365×59365×59365)= (59365)4