good one
E) (-2)^-n = -2^-n
n = 0
(-2)^-0 = -2^-0
1 = -1
n = 1
(-2)^-1 = -2^-1
-0.5 = -0.5
n = 1 is a solution, so this answer is incorrect
(D) (-2)^n = -2^n
n = 0
(-2)^0 = -2^0
1 = -1
n = 1
(-2)^1 = -2^1
-2 = -2
n = 1 is a solution, so this answer is incorrect
(C) 2^n = (-2)^-n
n = 0
2^0 = (-2)^-0
1 = 1
n = 0 is a solution, so this answer is incorrect
(B) 2^-n = (-2)^n
n = 0
2^-0 = (-2)^0
1 = 1
n = 0 is a solution, so this answer is incorrect
(A) -2^n = (-2)^-n
n = 0
-2^0 = (-2)^-0
-1 = 1
n = 1
-2^1 = (-2)^-1
-2 = -0.5
n = 0
(-2)^-0 = -2^-0
1 = -1
n = 1
(-2)^-1 = -2^-1
-0.5 = -0.5
n = 1 is a solution, so this answer is incorrect
(D) (-2)^n = -2^n
n = 0
(-2)^0 = -2^0
1 = -1
n = 1
(-2)^1 = -2^1
-2 = -2
n = 1 is a solution, so this answer is incorrect
(C) 2^n = (-2)^-n
n = 0
2^0 = (-2)^-0
1 = 1
n = 0 is a solution, so this answer is incorrect
(B) 2^-n = (-2)^n
n = 0
2^-0 = (-2)^0
1 = 1
n = 0 is a solution, so this answer is incorrect
(A) -2^n = (-2)^-n
n = 0
-2^0 = (-2)^-0
-1 = 1
n = 1
-2^1 = (-2)^-1
-2 = -0.5
Median mean and deviation properties
median of a set is greater than the mean, however, the terms below the median must collectively be farther from the median than the terms above the median.
hidden variables are tricky
http://www.beatthegmat.com/gmat-prep-t56323.html
You should see the ans B to see if thats ticking you by having the same equation
Inequality
1.) is x-y>10, is x-y>x+y
a. x=8
b. y =-20
taking A alone.. -y>2 => y<-2 hence y is -ve hence x-y>x+y suff
taking B... y=-20, => x>-10
suppose x = -9, x-y = 11, x+y = -29
suppose x = 9, x-y = -29, x+y = -11
Insuff
ans A
2.) Remainder when x is divided by 6..
A - x/2 - rem is 1 => x is odd
x/3 - rem is 0 => x is multiple of 3
hence x can be odd nos multiples of 3 - 3,9,15,21 ...whenever divided by 6 ..rem is 3 => A is suff
B - x/12 - rem is 3 => x = 12 * k +3 => x = 2 * (6k) + 3 => rem always 3
=> B is suff
ans D
3.) is m+z>0
neither statement alone is sufficient as nature of m and z is not known
combining we get z>0 => m>3z hence m+z is always +ve
ans C
4.) I missed this one big time...
earlier i thought it to be C..but agreed to one of the explanations provided above...
taking A alone - q=11 to 16 -> insuff
taking B alone - q = 2, 4, 8, 16 -> rem is always 1
ans B
5.) has been very well explained by ravindra_iit..it was a question i had posted day before for clarification...
is x-y/x+y>1
=> is (x-y/x+y)-1>0
=> is -2y/x+y>0.
=>is y/(x+y)<0
it is true when y<0 & x+y>0 or y>0 & x+y<0
a. x>0 insuff
b. y<0 insuff
both together insuff
ans is E...OA is E (question from OG11)
6.) is 1/p > r / (r^2 +2)
taking A - p=r => 1/r > r/(r^2 + 2) -> nature or r is not known..insuff
taking B - nor relation given -> insuff
together as r>0
it can be cross multiplied to get r^2+2 > r^2 always true
hence ans is C ....OA is also C...its a OG11 question
a. x=8
b. y =-20
taking A alone.. -y>2 => y<-2 hence y is -ve hence x-y>x+y suff
taking B... y=-20, => x>-10
suppose x = -9, x-y = 11, x+y = -29
suppose x = 9, x-y = -29, x+y = -11
Insuff
ans A
2.) Remainder when x is divided by 6..
A - x/2 - rem is 1 => x is odd
x/3 - rem is 0 => x is multiple of 3
hence x can be odd nos multiples of 3 - 3,9,15,21 ...whenever divided by 6 ..rem is 3 => A is suff
B - x/12 - rem is 3 => x = 12 * k +3 => x = 2 * (6k) + 3 => rem always 3
=> B is suff
ans D
3.) is m+z>0
neither statement alone is sufficient as nature of m and z is not known
combining we get z>0 => m>3z hence m+z is always +ve
ans C
4.) I missed this one big time...
earlier i thought it to be C..but agreed to one of the explanations provided above...
taking A alone - q=11 to 16 -> insuff
taking B alone - q = 2, 4, 8, 16 -> rem is always 1
ans B
5.) has been very well explained by ravindra_iit..it was a question i had posted day before for clarification...
is x-y/x+y>1
=> is (x-y/x+y)-1>0
=> is -2y/x+y>0.
=>is y/(x+y)<0
it is true when y<0 & x+y>0 or y>0 & x+y<0
a. x>0 insuff
b. y<0 insuff
both together insuff
ans is E...OA is E (question from OG11)
6.) is 1/p > r / (r^2 +2)
taking A - p=r => 1/r > r/(r^2 + 2) -> nature or r is not known..insuff
taking B - nor relation given -> insuff
together as r>0
it can be cross multiplied to get r^2+2 > r^2 always true
hence ans is C ....OA is also C...its a OG11 question