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Re: Of the following, which is the best approximation to 0.0026^1/2 ?
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01 Mar 2010, 13:49

1

When you have square or cubed roots of numbers that are less than 0 you can use the following. For square roots:

Square root the number at the end of the decimal (so if it were (0.0026)^0.5, you would square root 26) and divide the number of decimal places by 2. In this case, we know that the square root of 26 is a tiny bit more than 5, and dividing the number of decimal places (4) by 2 gives you 2 decimal places. Thus the answer is approximately 0.05

Cube root of a number: same procedure as above, but we cube root the number at the end of the fraction and divide the number of decimal places by 3.

Re: Of the following, which is the best approximation to 0.0026^1/2 ?
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06 Mar 2010, 10:55

abhi758 wrote:

Of the following, which is the best approximation to \(\sqrt{0.0026}\)? (A) 0.05 (B) 0.06 (C) 0.16 (D) 0.5 (E) 0.6

Kindly provide the steps to the solution. OA to be posted soon.

Square root of a number that has four digits to the right of decimal would have two digits to the right of decimals in the solution. So by this we rule out option D & E

Now the approx value of (26)^1/2 would be 5. The solution would therefore be A.

Re: Of the following, which is the best approximation to 0.0026^1/2 ?
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06 Mar 2010, 16:48

this is how I did it.... nearest to 26 is 25..root of this is 5 therefore, btw a) and d) with 2 zeros before the decimal point, I took .05*.05 = 0.0025

If you are looking for online GMAT math tutoring, or if you are interested in buying my advanced Quant books and problem sets, please contact me at ianstewartgmat at gmail.com

Re: Of the following, which is the best approximation to 0.0026^1/2 ?
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24 Oct 2017, 06:42

abhi758 wrote:

Of the following, which is the best approximation to \(\sqrt{0.0026}\)?

(A) 0.05 (B) 0.06 (C) 0.16 (D) 0.5 (E) 0.6

Since 0.05^2 = 0.0025 and 0.06^2 = 0.0036, we see that √0.0026 is between 0.05 and 0.06. However, since 0.0026 is closer to 0.0025 than it is to 0.0036, √0.0026 is closest to 0.05.

Answer: A
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