Data Sufficiency (DS) | Re: A certain salesman's yearly income is determined by a base

Income - I
Commission - C
Base Salary - B

Originally last year - I = B + C

Option 1 -
B + 1.3C = 1.1I
Subtract this from the original equation
We get - 0.1I = 0.3C
Or C = 0.33I
This means that Base was 0.67 of I which is greater than 50%
Sufficient

Option 2 -
Since we are not given whether B > C - we should consider it both ways. First if B was greater than C -

B - C = 0.5B
C = 0.5B
Replacing in original equation
I = B + 0.5B
B = 0.66I

Hence this answers as yes, base salary accounts for
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