For years, telephone area codes in the united states and canada consisted of a sequence of three digits. the first digit was an integer between 2 and 9, the second digit was either 0 or 1, and the third digit was any integer from 1 to 9. how many area codes starting with a 4 were possible?

The question illustrates permutation and combination.

The total number of area codes starting with 4 is 18.

The selection is as follows:

The total number of selection is:

Hence, 18 area codes starting with 4 are possible.

Read more about permutation and combination at:

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The first number had to be 4, so only one option for the first number.

The second number was either 0 or 1, so two options for the second number.

The third number was between 1 and 9, so nine options for the third number.

Multiply each number of options together for total options:

1 x 2 x 9 = 18 different codes could start with 4.

idk

step-by-step explanation:

maybe try   if it is work from a book, if not try

the central idea is that:

individuals should refuse to cooperate with institutions they believe unjust.

thoreau felt  that governments were more often agents of corruption than justice, even democracies, and that just because the majority feels a certain way does not make it just or correct in absolute terms. he uses the fact that slavery exists in our democracy to support this idea.

he goes on to say that, as a result, people should live true to their own internal laws regarding right and wrong, as a product of reflection and a moral life, rather than following every law that society imposes. 

step-by-step explanation: