Question 595375: I need help with this math problem.Its a multiple choice & i need to know how you got the answer.
A new area code has been created. The phone number will have 7 digits, but the first digit cannot be 0 or 1. How Many phone numbers are possible in the new area code ?
A- 800,000
B- 1,000,000
C- 8,000,000
D- 80,000,000
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! There are 10 single digit numbers: 0,1,2,3,4,5,6,7,8,9
Of these, only 2-9 can be used for the first digits. So there are 10-2 = 8 choices for the first slot.
The rest can use any of the ten listed above.
From here, you simply multiply out the possible choices
(# of choices for first slot)*(# of choices for second slot)...(# of choices for last slot)
8*10*10*10*10*10*10 <<--- There are 6 copies of 10 being multiplied here
8*10^6
8*1,000,000
8,000,000
So there are 8,000,000 (eight million) possible phone numbers.
So the answer is choice C
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