are you sure its B?
IMO its C
from stm1 and stmt2 we get 2 values of a and b hence both not sufficient, using both, we can pick 1 value of a and b.
Integers A and B
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Source: Beat The GMAT — Data Sufficiency |
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linkinpark
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sunil_snath
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from stmt1, we get
a^3-a^2-b = 49
a(a^2-a)-b = 49
12a-b = 49 => NOT SUFFICIENT
from stmt2, we get
b^2-b-2 = 0
b = 2, -1
now only when b=-1 will we get an integer value of a = 4, so stmt2 is SUFFICIENT
So i think thats how we get B, but without the ans i would have chosen C as well
a^3-a^2-b = 49
a(a^2-a)-b = 49
12a-b = 49 => NOT SUFFICIENT
from stmt2, we get
b^2-b-2 = 0
b = 2, -1
now only when b=-1 will we get an integer value of a = 4, so stmt2 is SUFFICIENT
So i think thats how we get B, but without the ans i would have chosen C as well
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ramsharma
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I would like to add a bitsunil_snath wrote:from stmt1, we get
a^3-a^2-b = 49
a(a^2-a)-b = 49
12a-b = 49 => NOT SUFFICIENT
from stmt2, we get
b^2-b-2 = 0
b = 2, -1
now only when b=-1 will we get an integer value of a = 4, so stmt2 is SUFFICIENT
So i think thats how we get B, but without the ans i would have chosen C as well
For Statement 1:a^2-a=12.The statement itself gives the value of"a".but it gives two values -3,and 4.hence not sufficient
explanation of statement 2 is explained well by Sunil;
RAM SHARMA
