#p# = ap3+ bp - 1 where a and b are constants, and #-5# = 3, what is the value of #5#?
A) 5
B) 0
C) -2
D) -3
E) -5
A) 5
B) 0
C) -2
D) -3
E) -5
Hi RiyaR,
This is an example of a "symbolism" question - in these situations, you're given a "made-up" math symbol, told what it means, then asked to perform some basic calculation with it.
From what you've written, I assume that "ap3" is meant to be A(P^3).
#P# = A(P^3) + BP - 1 is the symbol/calculation we need to use.
We're told that #-5# = 3, so let's plug in -5 and see what we have...
A[(-5)^3)] +B(-5) - 1 = 3
-125A -5B = 4
Let's leave this for now and look at what we're asked to figure out....
#5# = ?
Now, let's plug in 5 and see what we have...
A(5^3) + 5B - 1
125A + 5B - 1
From earlier, remember that...
-125A - 5B = 4
Here we have....
125A + 5B
It's the same thing, but everything has the opposite "sign"...This tells us:
125A + 5B = -4
Plugging this value back in....
(125A + 5B) - 1
-4 -1 = -5
Final Answer: E
GMAT assassins aren't born, they're made,
Rich
