9
30,25,15,20, or 10.
Oh, dude, you're making me do math now? Alright, so if you have three numbers and you're asking how many combinations you can make with those three numbers, it's like a little math puzzle. Each number can be used multiple times, so it's like a little party for those numbers. The total number of combinations you can make with three numbers is 27. That's like having 27 different outfits to choose from for a night out, but with numbers.
10 You can only have one choice, the number 4 as the hundred digit and also one choice, the number 5 as the units digit. However, you can have any integer from 0-9 as the hundreds digit. The number of combinations is thus 1 x 10 x 1 = 10.
Three possible combinations: 17+1, 13+5 and 7+11.
The answer will depend on how many digits there are in each of the 30 numbers. If the 30 numbers are all 6-digit numbers then the answer is NONE! If the 30 numbers are the first 30 counting numbers then there are 126 combinations of five 1-digit numbers, 1764 combinations of three 1-digit numbers and one 2-digit number, and 1710 combinations of one 1-digit number and two 2-digit numbers. That makes a total of 3600 5-digit combinations.
9
6 ways: 931,913,139,193,391,319
30,25,15,20, or 10.
10 You can only have one choice, the number 4 as the hundred digit and also one choice, the number 5 as the units digit. However, you can have any integer from 0-9 as the hundreds digit. The number of combinations is thus 1 x 10 x 1 = 10.
There are 28706 such combinations. 5456 of these comprise three 2-digit numbers, 19008 comprise two 2-digit numbers and two 1-digit numbers, 4158 comprise one 2-digit number and four 1-digit numbers and 84 comprise six 1-digit numbers.
21
Only three: 12, 13 and 23. Remember that the combinations 12 and 21 are the same.
There are no three-digit numbers that equal 17. In fact, there are no numbers with more or less than two digits that equal 17. In fact, in the whole infinite supply of numbers, there is only one single number that equals 17. That number is . . . . . . . 17 .
21.
Three possible combinations: 17+1, 13+5 and 7+11.
NOT AN ANSWER:More acceptable combinations:1231 3213 2321More unacceptable combinations:1112 2222 3113Thanks.