Question

Suppose you are to select a password of size 4. The first character should be any lowercase letter or a digit, while the second should be a non-zero digit. The third should be any lower case letter, and the fourth should be any lowercase letter, which is different from the third. b. Consider a group of ten students, and six of them are boys. A committee of 3 students is expected to select from the above group. How many committees can you select with at least two girls

Answer 1

First question seems incomplete :

Answer:

40 ways

Step-by-step explanation:

Question B:

Number of boys = 6

Number of girls = 4

Number of people in committee = 3

Number of ways of selecting committee with atleast 2 girls :

We either have :

(2 girls 1 boy) or (3girls 0 boy)

(4C2 * 6C1) + (4C3 * 6C0)

nCr = n! ÷ (n-r)!r!

4C2 = 4! ÷ 2!2! = 6

6C1 = 6! ÷ 5!1! = 6

4C3 = 4! ÷ 1!3! = 4

6C0 = 6! ÷ 6!0! = 1

(6 * 6) + (4 * 1)

36 + 4

= 40 ways