SOLUTION: until recently U.S. telephone area codes were three-digit numbers whose middle digit was 0 or 1.codes whose last two digitsw are 1's are used for other purposes(for example,911).wi

Algebra ->  Permutations -> SOLUTION: until recently U.S. telephone area codes were three-digit numbers whose middle digit was 0 or 1.codes whose last two digitsw are 1's are used for other purposes(for example,911).wi      Log On