GRE Prep Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Which of the following options should be the least value of
[#permalink]
15 Oct 2015, 10:30
15 Oct 2015, 10:30
1
2
Bookmarks
00:00
Question Stats:
74% (01:27) correct
25% (01:10) wrong based on 27 sessions
Hide Show timer Statistics
Which of the following options should be the least value of n that satisfies the inequality, \(2^n > (10^{15})\) ?
A. 30
B. 45
C. 60
D. 75
E. 90
and the right answer is 60
please explain as I could not even get the sense on how to start solving it.
A. 30
B. 45
C. 60
D. 75
E. 90
and the right answer is 60
please explain as I could not even get the sense on how to start solving it.
Re: Inequalities
[#permalink]
09 Oct 2017, 20:04
09 Oct 2017, 20:04
1
1
(2)^n > 10^15
\divide the powers by n
2 > 10^(15/n)
if n = 30
2 < 10^(15/30)
2 < sqrt(10)
which is incorrect.
if n = 45
2 < 10^(15/45)
2 < cuberoot(10)
which is incorrect.
if n = 60
2 > 10^(15/60)
2 > (10)^(1/4).
therefore least value of n = 60.
\divide the powers by n
2 > 10^(15/n)
if n = 30
2 < 10^(15/30)
2 < sqrt(10)
which is incorrect.
if n = 45
2 < 10^(15/45)
2 < cuberoot(10)
which is incorrect.
if n = 60
2 > 10^(15/60)
2 > (10)^(1/4).
therefore least value of n = 60.
Re: Inequalities
[#permalink]
14 Oct 2017, 23:46
14 Oct 2017, 23:46
3
Sujan Sareen wrote:
Which of the following options should be the least value of n that satisfies the inequality, 2^n > (10^15) ?
options are:
30
45
60
75
90
and the right answer is 60
please explain as I could not even get the sense on how to start solving it.
options are:
30
45
60
75
90
and the right answer is 60
please explain as I could not even get the sense on how to start solving it.
2^10 >10^3
Now write
(2^10)^5 > (10^3)^5
The answer should be 50. 45 makes it less, so choose 60.
