123 132 231 213 312 321
6 - 123, 132, 213, 231, 312, and 321.
You can make 6 combinations with 3 numbers. They are: 123 213 312 132 231 321 * * * * * NO! Those are permutations! In combitorials, the order does not matter so that the combination 123 is the same as the combination 132 etc. So all of the above comprise just 1 combination. With three numbers you can have 1 combination of three numbers (as discussed above), 3 combinations of 2 numbers (12, 13 and 23) 3 combinations of 1 number (1, 2 and 3) In all, with n numbers you can have 2n - 1 combinations. Or, if you allow the null combination (that consisting of no numbers) you have 2n combinations.
The order of the digits in a combination does not matter. So 123 is the same as 132 or 312 etc. There are 10 combinations using just one of the digits (3 times). There are 90 combinations using 2 digits (1 once and 1 twice). There are 120 combinations using three different digit. 220 in all.
Find three consecutive positive even integers whose sum is 123 , Answer
Just one. In combinatorials, 123 is the same as 312 and so on.
6
6 for example, 123 123 132 321 213 231 312 * * * * * WRONG. Those are permutations, not combinations. There are 8 possible combinations: 123 12 13 23 1 2 3 and finally, the null combination.
Just 4: 123, 124, 134 and 234. The order of the numbers does not matter with combinations. If it does, then they are permutations, not combinations.
Six combinations: 123, 132, 213, 231, 312, 321
123 132 231 213 312 321
well, 123 213 312 321 132 231 that's all
123 132 213 231 312 321
Assuming the digits are not repeated, there are four combinations:123, 124, 134 and 234.
You can make six different combinations: 123 132 213 231 321 312. If you just need to know the number of combinations, you could find the answer without writing everything out by letting x represent the number of digits and calculating x*(x-1).
6 - 123, 132, 213, 231, 312, and 321.
You can make 6 combinations with 3 numbers. They are: 123 213 312 132 231 321 * * * * * NO! Those are permutations! In combitorials, the order does not matter so that the combination 123 is the same as the combination 132 etc. So all of the above comprise just 1 combination. With three numbers you can have 1 combination of three numbers (as discussed above), 3 combinations of 2 numbers (12, 13 and 23) 3 combinations of 1 number (1, 2 and 3) In all, with n numbers you can have 2n - 1 combinations. Or, if you allow the null combination (that consisting of no numbers) you have 2n combinations.