sanyalpritish wrote:What is the value of v³ - k³ ?
(1) vk > 0
(2) v - k = 6
Target question: v³ - k³?
Statement 1: vk > 0
This statement doesn't
FEEL sufficient, so I'll TEST some values.
There are several values of v and k that satisfy statement 1. Here are two:
Case a: v = 1 and k = 1, in which case
v³ - k³ = 1³ - 1³ = 0
Case b: v = 2 and k = 1, in which case
v³ - k³ = 2³ - 1³ = 7
Since we cannot answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Aside: For more on this idea of plugging in values when a statement doesn't feel sufficient, you can read my article: https://www.gmatprepnow.com/articles/dat ... lug-values
Statement 2: v - k = 6
This statement doesn't
FEEL sufficient either, so I'll TEST some values.
There are several values of v and k that satisfy statement 2. Here are two:
Case a: v = 7 and k = 1, in which case
v³ - k³ = 7³ - 1³ = some big number
Case b: v = 8 and k = 2, in which case
v³ - k³ = 8³ - 2³ = a DIFFERENT big number
Since we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
NOTE: I'm not going to waste time calculating 7³ - 1³ and 8³ - 2³. A see that they evaluate to be different values, which means I can't answer the target question. That's all I need to know.
Statements 1 and 2 combined
NOTICE that the numbers I tested for statement 2 ALSO satisfy statement 1. We have:
Case a: v = 7 and k = 1, in which case
v³ - k³ = 7³ - 1³ = some big number
Case b: v = 8 and k = 2, in which case
v³ - k³ = 8³ - 2³ = a DIFFERENT big number
Since we cannot answer the
target question with certainty, the combined statements are NOT SUFFICIENT
Answer =
E
Cheers,
Brent
