Given a,b,c are all positive
Question:
a(b-c) = 0 ??
If we prove a=0 or b=c(i.e. b-c=0) then a(b-c)=0
Stmt I
b-c=c-b
2b=2c
b=c
b-c is 0 We really dont need any info about a and we can safely say
a(b-c)=0
SUFF
Stmt II
b/c = c/b
b^2 = c^2
b=c (since both are positive If they were not given as positive then b=c or b=-c or c=b or c=-b)
a(b-c) will be 0
SUFF
Choose D)
GmatPrep + equal
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Source: Beat The GMAT — Data Sufficiency |
question a(b-c)= 0?
for it to be true, you either nee
a=0
b-c = 0 or b=c
1. b-c = c-b
move the same letter to same side then you get 2b = 2c, divide both by 2, then you get b=c. So a(b-c) is a(0) = 0
sufficient
2. b/c = c/b
i had to modify this portion.
b^2 = c^2,
as cramya said, they're both positive. so they're equal.
your answer is D
for it to be true, you either nee
a=0
b-c = 0 or b=c
1. b-c = c-b
move the same letter to same side then you get 2b = 2c, divide both by 2, then you get b=c. So a(b-c) is a(0) = 0
sufficient
2. b/c = c/b
i had to modify this portion.
b^2 = c^2,
as cramya said, they're both positive. so they're equal.
your answer is D
