Question 23

According to birth registration data available with the South Delhi Municipal Corporation,7 babies were born in a particular week in a private hospital. What is the probability that three babies were born on the same day of the week?

Solution

The three babies who are born on the same day of the week can be selected in $$^{^7}C_3$$ ways

The number of ways in which a particular day can be selected = 7

The remaining four babies can be born in 6*5*4*3 ways

The probability that three babies were born on the same day of the week =$$\frac{^{^7}C_3*7*6*5*4*3}{7^7}$$
=$$\ \frac{\ 1800}{7^5}$$

A is the correct answer.

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