Nine people can be selected from the group of 12 in
(12 x 11 x 10 x 9 x 8 x 7 x 6 x 5 x 4) = 79,833,600ways.
But each group of the same 9 people can be selected in
(9 x 8 x 7 x 6 x 5 x 4 x 3 x 2) = 362,880 different orders.
So the number of different 9-person committees that can be selected is
79,833,600/362,880 = 220 .
There are 8 ways to choose the first book There are 7 ways to choose the second book - 8 x 7 = 56 ways to select two books There are 6 ways to choose the third book - 8 x 7 x 6 = 336 way to select three books There are 5 ways to choose the fourth book - 8 x 7 x 6 x 5 = 1,680 ways to select four books.
For the first spot, you can choose any one of 5 students. For the second spot, you can choose any one of the remaining 4 students. For the third spot, you can choose any one of the remaining 3 students. etc. So the answer is: 5x4x3x2x1 = 120
Combination of three people from a group of 10 = (n!)/[r! x (n-r)!], where n = 10 and r = 3. The answer is therefore (10.9.8.7.6.5.4.3.2.1)/[(1.2.3) x (1.2.3.4.5.6.7)] = (10.9.8)/(1.2.3) = 10.3.4 = 120 ways
I Dont Know [210]
The answer is 10 over 3 (you write 10 over 3, without a fraction line in between, and with parentheses around the entire expression). This is calculated as (10 x 9 x 8) / (1 x 2 x 3).
7C4 = 35
12C9 = 220
Any 4 from 7 = 35 ways
7*6*5*4/(4*3*2*1) = 35 ways
7
-1
There are 45360 ways.
40 x 39 x 38 x 37 = 2193360
There are 14C8 = 14*13*12*11*10*9/(6*5*4*3*2*1) = 3003 ways.
For this type of problem, order doesn't matter in which you select the number of people out of the certain group. We use combination to solve the problem.Some notes to know what is going on with this problem:• You want to form a committee of 2 teachers and 5 students to be formed from 7 teachers and 25 students • Then, you select 2 teachers out of 7 without repetition and without considering about the orders of the teachers.• Similarly, you select 5 students out out 25 without repetition and without considering about the orders of the students.Therefore, the solution is (25 choose 5)(7 choose 2) ways, which is equivalent to 1115730 ways to form such committee!
house has 106
18x17= 306 ways