Question

Solve: 

4

x−y

 +  1

x+y

= 3 ;  2

x−y

 - 

3

x+y

= 5​

Answer 1

Step-by-step explanation:

Statement 1:

Multiply both sides by 3 to get:

Rewrite as:

There are several values of x and y that satisfy the above equation. Here are two:

Case a: x = 1 and y = 1. In this case, the answer to the target question is YES, x EQUALS y

Case b: x = 3 and y = 5. In this case, the answer to the target question is NO, x does NO equal y

Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2:

Multiply both sides by 4 to get:

Add y to both sides to get:

PERFECT! The answer to the target question is YES, x EQUALS y

Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: B