1) Is quadrilateral Q a square?

(1) The sides of Q have the same length.
(2) The diagonals of Q have the same length.

from one ( it is either a rhombus or square)......not suff

from two

it could be a rectangle or a square

both together

it is a square ........suff C is my answer



3) If the price of a magazine is to be doubled, by what percent will the number of magazines sold decrease?

(1) The current price of the magazine is $1.00.
(2) For every $0.25 of increase in price, the number of magazines sold will decrease by 10 percent of the number sold at the current price.

number sold at current price = x

current price per magazine = y

if price became = 2y what is decrease in x


from one ......not suff

from two

no idea about current price ....insuff

both together

current price is 1 thus increasing it to be 2 means 0.25*4 increase

thus the number sold wil decrease by 10%*4 = 40%

C is my answer


23. S is a set of integers such that
i) if a is in S, then –a is in S, and
ii) if each of a and b is in S, then ab is in S.
Is –4 in S?

(1) 1 is in S.
(2) 2 is in S.

from one

1 , -1 is in S ...NOT SUFF

FROM TWO

2,-2 IS in S and -2*2 = -4 is in S........SUFF

MY ANSWER IS B


19. Does x + y = 0?

(1) xy<0
(2) x2 = y2

FROM STEM

X = -Y ( IE : SAME ABSOLUTE VALUES AND DIFFERENT DIRECTIONS )

FROM ONE

XY HAS DIFFERENT SIGNS ..NOT SUFF

FROM TWO

/X/ = /Y/ .........NO IDEA ABOUT SIGNS .........NOT SUFF

BOTH SUFF

MY ANSWER IS C

2) The surface area of a square tabletop was changed so that one of the dimensions was reduced by 1 inch and the other dimension was increased by 2 inches. What was the surface area before these changes were made?

(1) After the changes were made, the surface area was 70 square inches.
(2) There was a 25 percent increase in one of the dimensions.

AFTER CHANGE IT BECAME A RECTANGLE

(L-1)( L+2) = New area


from one

(L-1)( L+2) = 70

L^2+L-72 = 0

(L+9)(L-8) = 0 THUS L = 8 ORIGINAL AREA = 64

FROM TWO

L+2 = 1.25 L 0.25L = 2 L = 8 AND AREA = 64

ANSWER IS D