A women student is to answer 10 out of 13 questions find the number of her choices where she must answer exactly 3 out of 5 questions.
Not sure just what you're after, and posting it twice does not help.
rebecca.hadden. email isaiah
To find the number of choices where the woman student must answer exactly 3 out of 5 questions, we can use the concept of combinations.
First, let's calculate the number of ways she can choose 3 questions out of the 5 total questions. This can be calculated using the combination formula, also known as "nCr", which gives the number of ways to choose r items from a set of n items.
The combination formula is given by:
C(n, r) = n! / (r! * (n - r)!)
Where "!" denotes the factorial operation.
In this case, we have n = 5 (the total number of questions) and r = 3 (the number of questions she must answer). Plugging these values into the combination formula, we get:
C(5, 3) = 5! / (3! * (5 - 3)!)
= 5! / (3! * 2!)
The value of 5! (5 factorial) is 5 * 4 * 3 * 2 * 1 = 120.
The value of 3! (3 factorial) is 3 * 2 * 1 = 6.
The value of 2! (2 factorial) is 2 * 1 = 2.
Now, let's substitute these values back into the formula:
C(5, 3) = 120 / (6 * 2)
= 120 / 12
= 10
Therefore, the number of choices where the woman student must answer exactly 3 out of 5 questions is 10.