Hey Coinsy,
Statement (1) taken alone
we can have
|a-b| = b - a
Condition 1: take a=b=3 or 4 or any other number
Then |3-3| = 3-3 = 0
Condition 2: Take a=1 and b =4
then |1-4| = 4-1 = 3
Condition 3: Take a=4 and b=1
the |4-1| = 3
1-4= -3
Condition three is not valid
Also |a-b| is always positive
so if b-a is always positive it means that b>a (excluding the case where the are equal)
So (1) is not sufficient as condition says that a=b and condition (2) says that a<b. Hence statement 1 is not sufficient
Statement (2)
a/b < 1
Condition 1: a=-5 and b = -10
this proves a/b < 1 as 0.5 < 1
but clearly a>b
Condition 2: a=5 and b =10
this proves a/b < 1 as 0.5 < 1
so a<b
Hence Statement (2) alone is not sufficient
Now consider (1) and (2) together
Recall that statement 1 is insufficient because we got 2 different values of a=b and a<b
similarly statement 2 is insufficient because we didn't know the sign of the a and b
Now a cannot be equal b because the statement 2 will be invalid similarly a>b then statement 1 will be valid
So combining both the statements we can say that a<b
hence the answer is C
Kudos if it helps