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# If a?b = 3a^2 + 2b − 1, then 2?3 =

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Math Expert
Joined: 02 Sep 2009
Posts: 53066
If a?b = 3a^2 + 2b − 1, then 2?3 =  [#permalink]

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13 Nov 2018, 00:37
00:00

Difficulty:

5% (low)

Question Stats:

93% (00:39) correct 7% (00:00) wrong based on 52 sessions

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If a?b = 3a^2 + 2b − 1, then 2?3 =

A. 12
B. 17
C. 30
D. 37
E. 41

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Manager
Joined: 11 Dec 2013
Posts: 114
Location: India
GMAT Date: 03-15-2015
WE: Education (Education)
Re: If a?b = 3a^2 + 2b − 1, then 2?3 =  [#permalink]

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13 Nov 2018, 01:00
2
If a?b = 3a^2 + 2b − 1, then 2?3 =3.2^2 + 2(3) − 1 = 12+6-1 =17
Hence B
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Posts: 1928
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
Re: If a?b = 3a^2 + 2b − 1, then 2?3 =  [#permalink]

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13 Nov 2018, 03:18
Bunuel wrote:
If a?b = 3a^2 + 2b − 1, then 2?3 =

A. 12
B. 17
C. 30
D. 37
E. 41

a=2 and b=3 put in eqn a?b = 3a^2 + 2b − 1
we get 17 option B
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Re: If a?b = 3a^2 + 2b − 1, then 2?3 =  [#permalink]

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13 Nov 2018, 03:59

Solution

Given:
• a?b = $$3a^2 + 2b - 1$$

To find:
• The value of 2?3

Approach and Working:
• 2?3 = $$3 * 2^2 + 2 * 3 – 1 = 12 + 6 – 1 = 17$$

Hence, the correct answer is Option B

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Manager
Joined: 24 Dec 2017
Posts: 182
Location: India
Concentration: Strategy, Real Estate
Schools: Johnson '21
Re: If a?b = 3a^2 + 2b − 1, then 2?3 =  [#permalink]

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13 Nov 2018, 07:16
a?b = 3a^2 + 2b - 1

a=2
b=3

2?3 => 3(2)^2 + 2(3) - 1
=> 3(4) + 6 - 1
=> 12 + 6 - 1
=> 18 - 1
=> 17

IMO B
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Joined: 12 Apr 2017
Posts: 60
Location: United States
Concentration: Finance, Operations
GPA: 3.1
Re: If a?b = 3a^2 + 2b − 1, then 2?3 =  [#permalink]

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13 Nov 2018, 10:33
B - 17

a?b = 3a^2 + 2B - 1

2?3 = 3(2)^2 + 2(3) - 1
3*4+6-1
12+6-1
18-1
17
Manager
Joined: 01 Mar 2015
Posts: 76
Re: If a?b = 3a^2 + 2b − 1, then 2?3 =  [#permalink]

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13 Nov 2018, 11:12
Bunuel wrote:
If a?b = 3a^2 + 2b − 1, then 2?3 =

A. 12
B. 17
C. 30
D. 37
E. 41

As a?b = 3a^2 + 2b − 1
Therefore 2?3 = 3*2^2 + 2*3 - 1
= 12 + 6 - 1
= 17

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Posts: 4972
Location: United States (CA)
Re: If a?b = 3a^2 + 2b − 1, then 2?3 =  [#permalink]

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27 Jan 2019, 18:44
Bunuel wrote:
If a?b = 3a^2 + 2b − 1, then 2?3 =

A. 12
B. 17
C. 30
D. 37
E. 41

Note that the ? is simply a symbol that denotes a relationship between a and b, and that relationship is given by the formula 3a^2 + 2b − 1. Thus, when we evaluate 2?3, we see that a = 2 and b = 3.

Substituting, we have:

2?3 = 3(2^2) + 2(3) - 1 = 12 + 6 - 1 = 17

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Re: If a?b = 3a^2 + 2b − 1, then 2?3 =   [#permalink] 27 Jan 2019, 18:44
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