Let's try to answer the following Data Sufficiency
question using as little calculation as possible.
What is the value of x?
1) If x were the length of the diameter of a circle,
the area of the circle would be three times greater than the
radius.
2) If x were the length of the circumference of
a circle, the ratio of x to the radius would be 2? :1.
1) If x were the length of the diameter of a circle,
the area of the circle would be three times greater than the
radius.
| |
|
Statement 1 is sufficient. |
|
Statement 1 is insufficient. |
|
Calculation is necessary. |
2) If x were the length of the circumference
of a circle, the ratio of x to the radius would
be 2? :1.
| |
|
Statement 2 is sufficient. |
|
Statement 2 is insufficient. |
|
Calculation is necessary. |
Countinue
We don’t have to work this one out either. It’s definitely
insufficient. How do we know? Because the ratio of circumference to radius
is always 2? :1,
regardless of the size of the circle. Why should you have known this?
Because it’s the formula for circumference of a circle. Skeptical?
Check
out the math.
So, our answer is Choice (A), Statement 1 alone is
sufficient. Let’s try another example.
Next to display next topic in the chapter.
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