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[x] is the greatest integer less than or equal x, what is the value of
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15 Mar 2021, 10:30
15 Mar 2021, 10:30
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Question Stats:
82% (01:02) correct
17% (00:45) wrong based on 34 sessions
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\([x]\) is the greatest integer less than or equal \(x\), what is the value of \([√30]+[√40]+[√50]?\)
\(A. 12\)
\(B. 15\)
\(C. 16\)
\(D. 18\)
\(E. 20\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
\(A. 12\)
\(B. 15\)
\(C. 16\)
\(D. 18\)
\(E. 20\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
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Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: [x] is the greatest integer less than or equal x, what is the value of
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15 Mar 2021, 10:33
15 Mar 2021, 10:33
Carcass wrote:
\([x]\) is the greatest integer less than or equal \(x\), what is the value of \([√30]+[√40]+[√50]?\)
\(A. 12\)
\(B. 15\)
\(C. 16\)
\(D. 18\)
\(E. 20\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
\(A. 12\)
\(B. 15\)
\(C. 16\)
\(D. 18\)
\(E. 20\)
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
GIVEN: [x] is the greatest integer less than or equal x
For example, [3.2] = 3, since 3 is the greatest integer that is less than (or equal) to 3.2
Likewise, [8.7] = 8, since 8 is the greatest integer that is less than (or equal to) 8.7
Now onto the question....
√25 = 5
√36 = 6
√49= 7
√64 = 8
Since √30 is BETWEEN √25 (aka 5) and √36 (aka 6), we know that √30 = 5.something
So, [√30] = 5
Since √40 is BETWEEN √36 (aka 6) and √49 (aka 6), we know that √40 = 6.something
So, [√40] = 6
Since √50 is BETWEEN √49 (aka 7) and √64 (aka 8), we know that √50 = 7.something
So, [√50] = 7
So, [√30]+[√40]+[√50] = 5 + 6 + 7 = 18
Answer: D
Cheers,
Brent
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Given Kudos: 172
Location: India
WE:Education (Education)
Re: [x] is the greatest integer less than or equal x, what is the value of
[#permalink]
15 Mar 2021, 23:27
15 Mar 2021, 23:27
Carcass wrote:
\([x]\) is the greatest integer less than or equal \(x\), what is the value of \([√30]+[√40]+[√50]?\)
\(A. 12\)
\(B. 15\)
\(C. 16\)
\(D. 18\)
\(E. 20\)
\(A. 12\)
\(B. 15\)
\(C. 16\)
\(D. 18\)
\(E. 20\)
\(5 ≤ \sqrt{30}\)
\(6 ≤ \sqrt{40}\)
\(7 ≤ \sqrt{50}\)
So, \(x = 5 + 6 + 7 = 18\)
Hence, option D
