If a < 0, is b < 0 ?

(1) b/a > 0. This implies that a and b have the same sign. Since it's given that a is negative, then b must be negative too. Sufficient.

(2) a - b > 0. Re-arrange: a > b. Given that 0 > a, so 0 > a > b. Sufficient.

Answer: D.
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a<0 i.e. a is negative.
S1 = b/a > 0 therefore, b also must be negative for b/a to be positive.
b<0 . Sufficient.
S2 = a - b > 0
i.e. a>b (Adding b to both sides, because adding or subtracting variables in both sides of inequalities is allowed, but multiplication or division is not allowed, if we don't know the sign of the variables - Refer to Inequalities theory for more details)
Since a<0, b must be <0, because a>b.
Sufficient.
Answer D.
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(1) says that b/a > 0, which implies that a and b have the same sign. Since it's given that a is negative, then b must be negative too. Sufficient.

Here b cannot be 0 because if it were then b/a would equal to 0 and not greater than 0.
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