d = 0.43t7 If t denotes the thousandths digit in the decimal

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d = 0.43t7
If t denotes the thousandths digit in the decimal representation of d above, what digit is t?

(1) If d were rounded to the nearest hundredth, the result would be 0.44.
(2) If d were rounded to the nearest thousandth, the result would be 0.436.

OA B

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by Jay@ManhattanReview » Thu Jan 03, 2019 2:37 am

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BTGmoderatorDC wrote:d = 0.43t7
If t denotes the thousandths digit in the decimal representation of d above, what digit is t?

(1) If d were rounded to the nearest hundredth, the result would be 0.44.
(2) If d were rounded to the nearest thousandth, the result would be 0.436.

OA B

Source: Official Guide
Given that d = 0.43t7, we have to find out the value of t.

Let's take each statement one by one.

(1) If d were rounded to the nearest hundredth, the result would be 0.44.

We have d = 0.43t7, which is rounded to the nearest hundredth and its value is 0.44.

Since the nearest hundredth is increased from '3' to '4,' t must be greater than equal to 5. Or, t is one among {5, 6, 7, 8, 9}. No unique value of t. Insufficient.

(2) If d were rounded to the nearest thousandth, the result would be 0.436.

We see that in d = 0.43t7, the ten thousandth digit 7, which is greater 4, thus, upon rounding d = 0.43t7, t must increase by 1, making it (t + 1). Again, since d rounded to the nearest thousandth is 0.436, (t + 1) = 6 => t = 5. Sufficient.

The correct answer: B

Hope this helps!

-Jay
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