Is ( y + 3)^2 less than 4 ? (1) y + 3 is less than 2. (2) y

Question

Is ( y + 3)^2 less than 4 ?

(1) y + 3 is less than 2.

(2) y + 3 is greater than -1/2. 


Please explain.

Highlight this row for answer.  OA is C

eschn3am · Answer

rephrase the question:

-5 < y < -1

1. y+3 is less than 2

y < -1 but doesn't tell us anything about being greater than -5

INSUFFICIENT

2. y + 3 > -1/2
y > -7/2 but doesn't tell us anything about being less than -1

INSUFFICIENT

together we see that y is between -7/2 and -1 (non inclusive) which falls within the range we set out in the question

SUFFICIENT

Answer C

pmenon · Answer

heres an absolutely simple question, and i hate to ask this as i should know it, but how do you come up with this ?

i know youre taking the square root of both sides, and that square root of 4 gives a plus/minus 2 . I get the y<-1 part, but not -5 ...

eschn3am · Answer

here is our original question:

 

What number squared equals 4? 

2^2 = 4
so 2-3 = -1
and Y must be less than -1

BUT

(-2)^2 = 4 as well
so -2-3 = -5

SO

Y must be greater than -5 but less than -1

if it's -6 then (-3)^2 = 9
if it's 0 then (3)^2 = 9

does that help?

pmenon · Answer

Thanks man !

I realized my mistake was not flipping around the sign with I was considering the negative root (i.e. -2) after taking the square root of both sides.

So I was ending up with y<-5 and y<-1 !

Is ( y + 3)^2 less than 4 ? (1) y + 3 is less than 2. (2) y

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