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03 Oct 2017, 00:05
Kudos
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E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
75%
(hard)
Question Stats:
50% (02:04) correct
50%
(02:05)
wrong
based on 377
sessions
History
Date
Time
Result
Not Attempted Yet
Is \(r^x<100\) ?
(1) \(r∗\sqrt[3]{x}>100\)
if x = 1/8
=> \(r∗\sqrt[3]{\frac{1}{8}}>100\)
=> \(r*\frac{1}{2} > 100\)
=> r > 200
\(r^x<100\)
=>\(300^{\frac{1}{8}}<100\) True
if x = 8
=> r > 50
\(r^x<100\)
=>\(51^{8}<100\) False
So here we don't have max and min of x and r, so we cannot calculate value of \(r^x<100\)
Insufficient
(2) x>1
Here we dont know value of r
Insufficient
1+2
\(r∗\sqrt[3]{x}>100\) and x>1
for x =8>1 => \(r∗\sqrt[3]{x}>100\)
=> \(r∗\sqrt[3]{8}>100\)
=> r >50
so \(r^x<100\)
=> \(51^8<100\) False
for x=100000000
\(r∗\sqrt[3]{x}>100\)
=> \(r∗\sqrt[3]{100000000}>100\)
=> r* 1000>100
=> r >1/10
so \(r^x<100\)
=> \(1^{1000000000}<100\) True
So here there is no max limit on x. Hence insufficient
Answer: E
(1) \(r∗\sqrt[3]{x}>100\)
if x = 1/8
=> \(r∗\sqrt[3]{\frac{1}{8}}>100\)
=> \(r*\frac{1}{2} > 100\)
=> r > 200
\(r^x<100\)
=>\(300^{\frac{1}{8}}<100\) True
if x = 8
=> r > 50
\(r^x<100\)
=>\(51^{8}<100\) False
So here we don't have max and min of x and r, so we cannot calculate value of \(r^x<100\)
Insufficient
(2) x>1
Here we dont know value of r
Insufficient
1+2
\(r∗\sqrt[3]{x}>100\) and x>1
for x =8>1 => \(r∗\sqrt[3]{x}>100\)
=> \(r∗\sqrt[3]{8}>100\)
=> r >50
so \(r^x<100\)
=> \(51^8<100\) False
for x=100000000
\(r∗\sqrt[3]{x}>100\)
=> \(r∗\sqrt[3]{100000000}>100\)
=> r* 1000>100
=> r >1/10
so \(r^x<100\)
=> \(1^{1000000000}<100\) True
So here there is no max limit on x. Hence insufficient
Answer: E
General Discussion
03 Oct 2017, 03:20
Kudos
Bookmarks
Ans : c
1. r * x^1/3 > 100
consider x= positive (eg x= 27 and r =50)
Putting the values 125>100
Substituting x and r values in the given equation , r^x>100
Consider x= negative (eg x= -1 and r = -101)
Putting the values 101>100
Substituting x and r values in the given equation ,
r^x<100
NOt sufficient .
1.x > 1.
Statement alone is not sufficient as r can be any value.
Combining the two and subsituting anyvalue of x>1 and r that satisfies equation 1 ,
r^x is not less than 100 anytime.
1. r * x^1/3 > 100
consider x= positive (eg x= 27 and r =50)
Putting the values 125>100
Substituting x and r values in the given equation , r^x>100
Consider x= negative (eg x= -1 and r = -101)
Putting the values 101>100
Substituting x and r values in the given equation ,
r^x<100
NOt sufficient .
1.x > 1.
Statement alone is not sufficient as r can be any value.
Combining the two and subsituting anyvalue of x>1 and r that satisfies equation 1 ,
r^x is not less than 100 anytime.
. Thanks for highlighting, will edit the solution 
