The maximum decimal integer that can be stored in memory of 8-bit word processor computer? Actually i am preparing for an exam and in the last year exam this que. was been asked. i.e  

The maximum decimal integer number that can be stored in memory of 8-bit word processor computer ?    

a) (128)10
b) (127)10
c) (129)10
d) (255)10    

Answer of this que. as given in the answer key is b) 127. And I have no idea how they arrived at this result.  

Acc. to my understanding, we have 8-bits, which is 28 = 256  so 255 should be the maximum integer which we can store.  

EDIT - An another very similar que. asked in same exam was

The maximum permissible integer in a computer with n-bit word processor and one  word per integer is equal to

a) 2 n - 1 - 1
b) 2 n - 1
c) 2 n - 1 + 1
d) 2 n + 1  

Its ans. is  a) 2 n - 1 - 1 (acc. to official ans. key).  

By putting n = 8 from above que. we got the answer 127. But again i am clueless how did they derived this answer too.
I got the same question in my technical informatics exam. The right answer was also 127, my professor explained signed integer is the default format, therefore the range would go from -128 to 127. You can display 256 distinct value, but the maximum would still be 127.