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The value of x is derived by summing a, b, and c and then rounding the

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The value of x is derived by summing a, b, and c and then rounding the [#permalink]

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Tough and Tricky questions: Decimals.



The value of x is derived by summing a, b, and c and then rounding the result to the tenths place. The value of y is derived by first rounding a, b, and c to the tenths place and then summing the resulting values. If a = 5.45, b = 2.98, and c = 3.76, what is y – x?

A. -0.1
B. 0
C. 0.05
D. 0.1
E. 0.2
[Reveal] Spoiler: OA

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Re: The value of x is derived by summing a, b, and c and then rounding the [#permalink]

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Hi Bunuel,

Great question. I found the easiest way to solve this was to Dive In and do the math.

To find x, we first sum a, b, and c, then round to the tenths place. 5.45 + 2.98 + 3.76 = 12.19, which rounds to 12.2.
To find y, we first round a, b, and c to the tenths place and them sum them. so 5.5 + 3.0 + 3.8 = 12.3.

We are looking for y - x, which gives us 12.3 - 12.2 = 0.1, or answer choice D.

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The value of x is derived by summing a, b, and c and then rounding the [#permalink]

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New post 26 Oct 2014, 18:19
y - x = 5.5 + 3.0 + 3.8 - (5.45 + 2.98 + 3.76)

y - x = 12.30 - 12.19(\(\approx {12.2})\)

y - x = 12.30 - 12.20 = 0.1

Answer = D

Just note the last digit after decimal

5.45 + 2.98 + 3.76

All are 5 & above, which indicates of upper approximation. This will provide y > x
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The value of x is derived by summing a, b, and c and then rounding the [#permalink]

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New post 26 Oct 2014, 21:12
Bunuel wrote:

Tough and Tricky questions: Decimals.



The value of x is derived by summing a, b, and c and then rounding the result to the tenths place. The value of y is derived by first rounding a, b, and c to the tenths place and then summing the resulting values. If a = 5.45, b = 2.98, and c = 3.76, what is y – x?

A. -0.1
B. 0
C. 0.05
D. 0.1
E. 0.2



Value of X = First Summing and then Rounding = a+b+c = 5.45+2.98+3.76 = 12.19 = 12.2
Value of Y = First Rounding and then Summing = a+b+c = 5.5+3.0+3.8 = 12.3

Therefore, Y - X = 12.3 - 12.2 = 0.1

Answer is D

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Re: The value of x is derived by summing a, b, and c and then rounding the [#permalink]

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New post 25 Sep 2017, 15:11
Just found this great tutorial about rounding.
https://magoosh.com/gre/2016/gre-math-rounding/

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Re: The value of x is derived by summing a, b, and c and then rounding the   [#permalink] 25 Sep 2017, 15:11
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