Bunuel
What is the value of y?
(1) The ratio of y to x is 3.
(2) The sum of y and x is 80.
Target question: What is the value of y? Statement 1: The ratio of y to x is 3 In other words, x/y = 3
There are infinitely many values of x and y that satisfy statement 1. Here are two:
Case a: x = 3 and y = 1. In this case, the answer to the target question is
y = 1Case b: x = 6 and y = 2. In this case, the answer to the target question is
y = 2Since we can’t answer the
target question with certainty, statement 1 is NOT SUFFICIENT
Statement 2: x + y = 80There are infinitely many values of x and y that satisfy statement 2. Here are two:
Case a: x = 1 and y = 79. In this case, the answer to the target question is
y = 79Case b: x = 2 and y = 78. In this case, the answer to the target question is
y = 78Since we can’t answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Statements 1 and 2 combined Statement 1 tells us x/y = 3, which means
x = 3y (after multiplying both sides of the equation by y)
Statement 2 tells us x + y = 80
Replace
x with
3y in the second equation to get:
3y + y = 80
When we solve this equation we get
y = 20Since we can answer the
target question with certainty, the combined statements are SUFFICIENT
Answer: C