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Subject Test Math 1

Question 25 of 32

beginning of content:
Tags:
SAT Subject Test
X invisible times equals left curly bracket 2 comma 3 comma 4 comma 5 comma 6 comma 7 comma 8 comma 9 right curly bracket
Y invisible times equals left curly bracket 0 comma 1 right curly bracket
Z invisible times equals left curly bracket 0 comma 1 comma 2 comma 3 comma 4 comma 5 comma 6 comma 7 comma 8 comma 9 right curly bracket

 

Before 1990, telephone area codes in the United States were three-digit numbers of the form x y z. Shown above are sets X, Y, and Z from which the digits x, y, and z, respectively, were chosen. How many possible area codes were there?

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919

Correct Answer: 
No

160

Correct Answer: 
Yes

144

Correct Answer: 
No

126

Correct Answer: 
No

20

Correct Answer: 
No

There are 8 possible digits for the first digit, x, of the area code, 2 possible digits for y, and 10 possible digits for z. Therefore, the number of possible area codes would be 8 invisible times cross times 2 invisible times cross times 10 invisible times equals 160. The correct answer is B.

Question Difficulty: 
hard