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09 Dec 2019, 01:04
Kudos
Bookmarks
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
65%
(hard)
Question Stats:
54% (02:03) correct
46%
(02:10)
wrong
based on 112
sessions
History
Date
Time
Result
Not Attempted Yet
If \(ab = -9\), what is the value of \(ab(a + b)\) ?
(1) \(a - b = √100\)
(2) \(ab^2 = -81\)
Are You Up For the Challenge: 700 Level Questions
(1) \(a - b = √100\)
(2) \(ab^2 = -81\)
Are You Up For the Challenge: 700 Level Questions
Archit3110
09 Dec 2019, 03:25
Kudos
Bookmarks
given ab=-9
possiblities ; -9,1 and 9,-1
#1
a-b=10
9-(-1) or 1-(-9)
so
\(ab(a + b)\) = we get +/-72
insufficinet
#2\(ab^2 = -81\)
possible only when a= -1 and b=9
sufficient
IMO B
possiblities ; -9,1 and 9,-1
#1
a-b=10
9-(-1) or 1-(-9)
so
\(ab(a + b)\) = we get +/-72
insufficinet
#2\(ab^2 = -81\)
possible only when a= -1 and b=9
sufficient
IMO B
Bunuel
10 Dec 2019, 00:47
Kudos
Bookmarks
1 stm -- seems sufficient at a glance, as we have two variables and two equations, but hold on.
after solving we get either a=1 b=-1 or a=-1 b=-9. Not Sufficient
2 stm -- \(ab^2=ab*b=-81\), We know ab=-9 so -9b=-81 b=9; Sufficient
I will bet on B
after solving we get either a=1 b=-1 or a=-1 b=-9. Not Sufficient
2 stm -- \(ab^2=ab*b=-81\), We know ab=-9 so -9b=-81 b=9; Sufficient
I will bet on B
