The homework for English class was to write a poem. The teacher wants to ask 4 students, 2 boys and 2 sirls, to read their poems for the class. If there are 10 boys and 15 girls, how many different combinations of 2 boys and 2 girls can the teacher select?
Q. The homework for English class was to write a poem. The teacher wants to ask 4 students, 2 boys and 2 sirls, to read their poems for the class. If there are 10 boys and 15 girls, how many different combinations of 2 boys and 2 girls can the teacher select?
Boys Combination Calculation: To find the number of combinations of 2 boys out of 10, we use the combination formula 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.For 2 boys out of 10, the calculation is C(10,2)=2!(10−2)!10!.
Boys Combination Result: Calculating C(10,2) gives us 2!×8!10!=(2×1)(10×9)=45.There are 45 different ways to choose 2 boys out of 10.
Girls Combination Calculation: Next, we find the number of combinations of 2 girls out of 15 using the same combination formula.For 2 girls out of 15, the calculation is C(15,2)=(2!(15−2)!)15!.
Girls Combination Result: Calculating C(15,2) gives us rac{15!}{2! imes 13!} = rac{(15 imes 14)}{(2 imes 1)} = 105.There are 105 different ways to choose 2 girls out of 15.
Total Combinations Calculation: To find the total number of combinations of 2 boys and 2 girls, we multiply the number of combinations for boys by the number of combinations for girls.The calculation is 45×105.
Total Combinations Result: Calculating 45×105 gives us 4725. There are 4725 different combinations of 2 boys and 2 girls that the teacher can select.
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