If a b and c are consecutive integers, in that order, what is the value of b?
I. `b = a+c`
II. `ac =-1`

Options

A. If statement (I) alone is sufficient to answer the question.
B. If statement (II) alone is sufficient to answer the question.
C. If either (I) or (II) alone is sufficient to answer the question.
D. If both statements (I) and (II) taken together are sufficient to answer the question.

Answer

C

Explanation

In this question, statement I can be rewritten as:
`a + 1=a + (a + 2)` [Substituting in equation b = a + c]
`therefore a =-1, and "so "b=0`.
Therefore, statement I is sufficient to answer the question. Statement II is also sufficient to answer the question.
`a(a+2) =-1`
`rArr a^(2) +2a +1=0`
`rArr (a+1) (a+1) =0`
So, `a=-1, and b = 0`
Therefore, the correct answer is choice (c)