A locker combination system uses three digits from 0 to 9. How many different three-digit combinations with no digit repeated are possible? The Answers are 30, 504, 720, 1000. Which one is it? I said 504.
2007-12-18 13:47:25 · 6 answers · asked by Josh Kaz 3 in Science & Mathematics ➔ Mathematics
720
On the first number, you have 10 different options
0 1 2 3 4 5 6 7 8 9
on the second, you can't repeat the first one, so then you have 9 more options. (suppose you choose 9)
0 1 2 3 4 5 6 7 8
on the third, you can't repeat the first two, so lets say you choose 8
0 1 2 3 4 5 6 7
10*9*8=720
2007-12-18 13:54:21 · answer #1 · answered by Tros 2 · 1⤊ 0⤋
10X9X8= 720
The first digit could be anything from 0-9 (ten choices) times the second, which could be anything from 0-9 minus the first digits (9 choices) and the last digit, which is anything from 0-9 minus the first two (8 choices)
2007-12-18 21:53:08 · answer #2 · answered by Annie G 1 · 0⤊ 0⤋
10 choices for 1st digit
9 choices for 2nd
8 for 3rd,
10(9)(8) = 720
2007-12-18 21:52:39 · answer #3 · answered by Philo 7 · 0⤊ 0⤋
I agree, 504.
9 x 8 x 7=504
9 possibilites for the first number
8 for the second number
and 7 possibilites for the third.
Right?
2007-12-18 21:51:52 · answer #4 · answered by ? 2 · 0⤊ 0⤋
720..check ur count again
2007-12-18 21:51:11 · answer #5 · answered by na cho baby 3 · 0⤊ 0⤋
tricky stuff. look using yahoo. this might help!
2014-11-12 04:32:01 · answer #6 · answered by Anonymous · 0⤊ 0⤋