Q. A club is going to send 4 of its 10 members to represent the club at a conference.How many different groups of 4 members can they send?
Calculate factorial of 10: To solve this problem, we need to calculate the number of combinations of 10 members taken 4 at a time. This is a combinatorial problem where order does not matter, and we can use the combination formula which is C(n,k)=k!(n−k)!n!, where n is the total number of items, k is the number of items to choose, and “!” denotes factorial.
Calculate factorial of 4: First, we calculate the factorial of 10, which is 10!=10×9×8×7×6×5×4×3×2×1.
Calculate factorial of difference: Next, we calculate the factorial of 4, which is 4!=4×3×2×1.
Apply combination formula: Then, we calculate the factorial of the difference between 10 and 4, which is 6!=6×5×4×3×2×1.
Substitute factorial values: Now we can plug these values into the combination formula: C(10,4)=4!×(10−4)!10!.
Simplify the equation: Substitute the factorial values into the formula: C(10,4)=(4×3×2×1)×(6×5×4×3×2×1)10×9×8×7×6×5×4×3×2×1.
Perform division and multiplication: We can simplify the equation by canceling out the common factors in the numerator and the denominator. The 6×5×4×3×2×1 in the denominator cancels with the same factors in the numerator, leaving us with: C(10,4)=4×3×2×110×9×8×7.
Final result: Perform the division and multiplication: C(10,4)=2410×9×8×7=90×7=630.
Final result: Perform the division and multiplication: C(10,4)=2410×9×8×7=90×7=630.Therefore, the club can send 630 different groups of 4 members to represent it at the conference.