Question number 4, Chapter number 5, Advanced GMAT Quant Gui

[Viroo100]

Question number 4, Chapter number 5, Advanced GMAT Quant Guide error-

The question is-
Q4-
What is the units digit of y?
(1) The units digit of y2 equals 6.
(2) The units digit of (y + 1)2 equals 5

Answear says. statement 2 alone is sufficient, but i See if we take
y= (-56) then (y+1)^2= (-55)^2= 3025- satisfy the condition with unit digits as 6

y= 54 then (y+1)= (55)^2= 3025, satisfy the condition, so if we consider Y as negative number then we will have one more value for Y and statement 1 will not be sufficient inthis case. So I think either Y must be positive number or ans choice must be E with both statement together not sufficient to ans. the question.

[tim]

the question should have mentioned explicitly that you are dealing only with positive numbers. if there is no indication that we are dealing with positive numbers then your analysis is correct..