What is the value of integer n? 1) n(n+2)=15 2) (n+2)^n=125

Question

What is the value of integer n?

1) n(n+2)=15
2) (n+2)^n=125

gmatnub · Answer

statement 1: n could be 3 or -5, insuff

statement 2: 125 = 5x5x5 --> n=3, suff

my guess is b

jcsekhar22 · Answer

from statement 1 we get n=3 or n= -5
and if we use the information from statement 2 we can say n=3

I think we need both statement to determine the value of n so C is the answer

lucyqin · Answer

I think the answer is B.

From statement 2 alone, we can determine that n = 3.

Maple · Answer

1) n(n+2)=15
n^2+2*n-15=0
(n+5)*(n-3)=0
n=-5 or 3
insufficient

2)
because (n+2)^n=125
n cannot be negative or a fractional value.
the cube root of 125 is 5
n=3
sufficient
 
B

GMATBLACKBELT · Answer

1: could be 3 or -5.

2: could be 3. or

(n+2)^n=5^3. 125=5^3 or 1/5^-3. But the second case will cause n to be a non-integer value. Thus I say,

B.

bkk145 · Answer

Bud, I can't agree with OA = C...
This is B.

bkk145 · Answer

In (2)...
(n+2)^n=125
125 = 5^3
This means
(n+2)^n = 5^3
n=3
SUFFICIENT

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