A seven-digit phone number is divisible by 9. After adding the two digits of the area code the number is not divisible by 9, which of the following cannot be the area code? Choose the correct answer: A) 07. B) 06. C) 05. D) 04. E) 09.
Given that 7 digit number is divisible by 9   we know any number will not be divisible by 9 if the sum of all digits of the number is not the multiple of 9.   Hence looking at the option we can say that the number that should be added to the seven digit number must be 09 as adding it will make it divisible by 9... hence answer is 09.
<result>E</result>
A seven-digit phone number is divisible by 9. After adding the two digits of the area code the number is not divisible by 9, which of the following cannot be the area code?