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If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=  [#permalink]

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Difficulty:   25% (medium)

Question Stats: 66% (00:59) correct 34% (01:03) wrong based on 246 sessions

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If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=

A. 27
B. 9
C. 3
D. 1
E. 1/3

Originally posted by reto on 11 Jun 2015, 13:15.
Last edited by Bunuel on 11 Jun 2015, 13:25, edited 1 time in total.
Edited the question.
Math Expert V
Joined: 02 Sep 2009
Posts: 60480
If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=  [#permalink]

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reto wrote:
If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=

A. 27
B. 9
C. 3
D. 1
E. 1/3

$$x∇y = 3*x^2*y$$

$$1∇1 = 3*1^2*1=3$$
$$1∇(1∇1)=1∇3 = 3*1^2*3=9$$

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Math Expert V
Joined: 02 Sep 2009
Posts: 60480
Re: If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=  [#permalink]

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Bunuel wrote:
reto wrote:
If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=

A. 27
B. 9
C. 3
D. 1
E. 1/3

$$x∇y = 3*x^2*y$$

$$1∇1 = 3*1^2*1=3$$
$$1∇(1∇1)=1∇3 = 3*1^2*3=9$$

Similar questions: Operations/functions defining algebraic/arithmetic expressions
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Posts: 12
If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=  [#permalink]

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1
I first thought the question stem said 3x^2 - Y. So, i guess everyone should be careful and note that there is no subtraction sign but that it is a multiplication (*) sign--- meaning : 3x^2 * Y.

Regardless of that note, yes the answer is 9! (B)

Originally posted by acarpio1 on 04 Jun 2016, 14:57.
Last edited by acarpio1 on 04 Jun 2016, 14:59, edited 1 time in total.
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Re: If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=  [#permalink]

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I haven't understood the question stem itself, can someone explain theoretically what does the question actually imply? Math Expert V
Joined: 02 Sep 2009
Posts: 60480
Re: If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=  [#permalink]

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1
Shef08 wrote:
I haven't understood the question stem itself, can someone explain theoretically what does the question actually imply? If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=

A. 27
B. 9
C. 3
D. 1
E. 1/3

Symbol ∇ here indicates a function, which does the following: for any two numbers x and y, x∇y equals to 3x^2*y. For example, if x = 5 and y = 10, then 5∇10 = 3*5^2*10 = 750.

The question asks to find the value of 1∇(1∇1). First deal with expression in brackets: (1∇1) = 3*1^2*1 = 3. So, now we should find the value of 1∇3, which is 3*1^2*3 = 9.

13. Functions

For more check below:
ALL YOU NEED FOR QUANT ! ! !

Hope it helps.
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Re: If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=  [#permalink]

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acarpio1 wrote:
I first thought the question stem said 3x^2 - Y. So, i guess everyone should be careful and note that there is no subtraction sign but that it is a multiplication (*) sign--- meaning : 3x^2 * Y.

Regardless of that note, yes the answer is 9! (B)

We also don't know if y is multiplied by the exponent or is a part of the equation, itself. If part of the exponent, the answer would be 3. Re: If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=   [#permalink] 20 Sep 2019, 03:36
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# If x∇y=3x^2·y for all x and y, then 1∇(1∇1)=  