Is 0<y<1?

[farooq]

Is 0<y<1?

(1) 0 < square root of 'y' < 1

(2) y^2=1/4


What can be the correct answer?

[scoobydooby]

Is 0<y<1? (is y a positive fraction?)

1) 0 < square root of 'y' < 1

=> square root of 'y' is a positive fraction
=>y is a positive fraction (squaring a positive fraction results in a positive fraction)
sufficient

2) y^2=1/4
y=1/2 or y=-1/2
since y can either be a positive or a negative fraction, not sufficient

hence A

[farooq]

Is 0<y<1? (is y a positive fraction?)

1) 0 < square root of 'y' < 1

=> square root of 'y' is a positive fraction
=>y is a positive fraction (squaring a positive fraction results in a positive fraction)
sufficient

2) y^2=1/4
y=1/2 or y=-1/2
since y can either be a positive or a negative fraction, not sufficient

hence A

You are right.

Why sqr root of 'Y' cannot be -ve as well as +ve?

Does sqrt root of any no. is always +ve?

[scoobydooby]

we need to find if y is between 0 and 1

sqr root of 'Y' can be -ve as well as +ve
to get y from the square root, we need to square it, so it becomes positive

say sq. root of y = 1/2 or -1/2
we want y
so y=(1/2 )^2 or (-1/2)^2
both gives y=1/4 (positive)

[scoobydooby]

farooq,
please refer to the last post in the link, Ian explains square root concept very well

https://www.beatthegmat.com/help-in-nump ... 29290.html