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