If a and b are integers, and b > 0, does a−1/b+1=a/b? (1) a = b − 4 (2) a =

If a and b are integers, and b > 0, does a−1/b+1=a/b? (1) a = b − 4 (2) a = –b Print

Modified on: Tue, 12 Oct, 2021 at 5:06 PM

Concept: The question tests on the application of using equations to reach at a conclusion in a DS format

Solution:

We are asked if a-1/b+1 = a/ b

Or we are asked if b (a-1) = a(b+1) [On cross multiplying]

Or if b a –b = a b + a

= > If a = -b ?

St (1) a= b-4

If b= 2 then a= 2-4 = -2 and hence a is EQUAL to –b (Yes)

However if b =4 a=0 and a is NOT EQUAL to –b (No )

Hence, two contradictory answers and thus St (1) is Insufficient

St (2) a = -b

It’s exactly what we are asking for in the question stem.

Thus sufficient. Option (B)

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If a and b are integers, and b > 0, does a−1/b+1=a/b? (1) a = b − 4 (2) a = –b Print