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If ∆ x = x for x ≥ 0 and 2x for x < 0,
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15 Mar 2021, 10:27
15 Mar 2021, 10:27
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If ∆ x = x for x ≥ 0 and 2x for x < 0, \(\frac{∆30}{∆(-5)}\)
A. −12
B. −6
C. −3
D. 6
E. 30
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
A. −12
B. −6
C. −3
D. 6
E. 30
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: If ∆ x = x for x ≥ 0 and 2x for x < 0,
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15 Mar 2021, 10:37
15 Mar 2021, 10:37
1
Carcass wrote:
If ∆ x = x for x ≥ 0 and 2x for x < 0, \(\frac{∆30}{∆(-5)}\)
A. −12
B. −6
C. −3
D. 6
E. 30
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
A. −12
B. −6
C. −3
D. 6
E. 30
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
∆x = x for x ≥ 0
In other words, IF x is greater than or equal to 0, then ∆x = x
So, for example, ∆5 = 5, and ∆11 = 11, and ∆0 = 0, since 5, 11 and 0 are all greater than or equal to 0
Likewise, ∆30 = 30
∆x = 2x for x < 0
In other words, IF x is less than 0, then ∆x = 2x
So, for example, ∆(-3) = 2(-3) = -6, and ∆(-1) = 2(-1) = -2, and ∆(-9) = 2(-9) = -18, since -3, -1 and -9 are all less than 0
Likewise, ∆(-5) = 2(-5) = -10
So....
∆30/∆(-5) = 30/(-10) = -3
Answer: C
Cheers,
Brent
gmatclubot
Re: If ∆ x = x for x ≥ 0 and 2x for x < 0, [#permalink]
15 Mar 2021, 10:37
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