If $ defines a certain operation, is p $ q less than 20?

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If $ defines a certain operation, is p $ q less than 20?

(1) x $ y = 2(x)^2 - y for all values of x and y

(2) p = 4, q = 10

Got lost on this one. Any ideas?

I think the answer is C b/c (1) gives you the operator and (2) gives you the values but I am having a tough time figuring out the operator :-/
Source: — Data Sufficiency |

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by selango » Tue Jun 01, 2010 9:16 am
the answer is indeed C

From stmt 1

x$y=2(x)^2-y

Lets x=p and y=q

p$q=2(p)^2-q -->A

We dont know the value of p and q,so insufficient.

From stmt2 only values are given but no equation to solve.So insufficient.

Combining both stmts,we can substitute the value of p and q in A and get the value of p$q

So C is correct

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by whatwasitodo » Tue Jun 01, 2010 9:20 am
hi, thanks for the help! do you think you could explain how to get the operator?

if P$Q = 2 P^2 - Q

What is $?

I tried plugging in (2)

4$10 = 2(4)^2 - 10
4$10 = 2(16) - 10
4$10 = 32-10
4$10 = 22 ?

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by selango » Tue Jun 01, 2010 9:26 am
The operator can be any symbol like *,+/- ans so.

The question is to verify if P$Q<20.What we need is value from the equation from right side.

So P$Q=2(4)^2-10

-->P$Q=22

Whenever the problem with some symbol occurs,we need to solve the equation defined by tat operator.

Hope this clarify.