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If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
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17 Jun 2017, 12:31
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If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true? (A) x > y > z (B) x < y < z (C) x^3 < y^2 < z (D) x^7 < y^5 < z^3 (E) x^10.5 > y^7.5 > z^4.5
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If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
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17 Jun 2017, 12:34
bkpolymers1617 wrote: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
(A) x > y > z
(B) x < y < z
(C) x^3 < y^2 < z
(D) x^7 < y^5 < z^3
(E) x^10.5 > y^7.5 > z^4.5 \(x^{3.5} > y^{2.5} > z^{1.5}\) Converting decimal power to fraction powers we get; \(3.5 = \frac{35}{10} = \frac{7}{2}\) \(2.5 = \frac{25}{10} = \frac{5}{2}\) \(1.5 = \frac{15}{10} = \frac{3}{2}\) \(x^{\frac{7}{2}} > y^{\frac{5}{2}} > z^{\frac{3}{2}}\) Cancelling common term \(\frac{1}{2}\) from the powers, we get; \(x^{7} > y^{5} > z^{3}\) Therefore (D) \(x^7 < y^5 < z^3\) cannot be true. Answer (D)...



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Re: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
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17 Jun 2017, 12:36
This is perfect. Yes D is the answer. Since we are dealing in positive numbers, i think square of the elements would not change signs. However, i was not able to understand C. Can you please help me understand how is C possible please. thanks.
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Re: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
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17 Jun 2017, 12:44
bkpolymers1617 wrote: This is perfect. Yes D is the answer. Since we are dealing in positive numbers, i think square of the elements would not change signs. However, i was not able to understand C. Can you please help me understand how is C possible please. thanks. Question says which option could not be true. I didn't check for all options which will be true or not. After simplifying the given exponents , we have \(x^7>y^5>z^3\) Hence we cannot have (D) \(x^7<y^5<z^3\). Hence D could not be true.



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Re: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
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18 Jun 2017, 18:06
How do we know the #s are positive? I simplified to X^7 etc like you did, but thought the #s could be negative and thus D could be true. Thanks! sashiim20 wrote: bkpolymers1617 wrote: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
(A) x > y > z
(B) x < y < z
(C) x^3 < y^2 < z
(D) x^7 < y^5 < z^3
(E) x^10.5 > y^7.5 > z^4.5 \(x^{3.5} > y^{2.5} > z^{1.5}\) Converting decimal power to fraction powers we get; \(3.5 = \frac{35}{10} = \frac{7}{2}\) \(2.5 = \frac{25}{10} = \frac{5}{2}\) \(1.5 = \frac{15}{10} = \frac{3}{2}\) \(x^{\frac{7}{2}} > y^{\frac{5}{2}} > z^{\frac{3}{2}}\) Cancelling common term \(\frac{1}{2}\) from the powers, we get; \(x^{7} > y^{5} > z^{3}\) Therefore (D) \(x^7 < y^5 < z^3\) cannot be true. Answer (D)...



Director
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Re: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
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29 Jun 2017, 17:39
mdacosta wrote: How do we know the #s are positive? I simplified to X^7 etc like you did, but thought the #s could be negative and thus D could be true. Thanks! sashiim20 wrote: bkpolymers1617 wrote: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
(A) x > y > z
(B) x < y < z
(C) x^3 < y^2 < z
(D) x^7 < y^5 < z^3
(E) x^10.5 > y^7.5 > z^4.5 \(x^{3.5} > y^{2.5} > z^{1.5}\) Converting decimal power to fraction powers we get; \(3.5 = \frac{35}{10} = \frac{7}{2}\) \(2.5 = \frac{25}{10} = \frac{5}{2}\) \(1.5 = \frac{15}{10} = \frac{3}{2}\) \(x^{\frac{7}{2}} > y^{\frac{5}{2}} > z^{\frac{3}{2}}\) Cancelling common term \(\frac{1}{2}\) from the powers, we get; \(x^{7} > y^{5} > z^{3}\) Therefore (D) \(x^7 < y^5 < z^3\) cannot be true. Answer (D)... \(x^{\frac{7}{2}} > y^{\frac{5}{2}} > z^{\frac{3}{2}}\) \(= \sqrt{x^{7}} > \sqrt{y^{5}} > \sqrt{z^{3}}\) After simplification of the expression we get that terms are square root of x, y and z, and square roots cannot have negative value. Hence the values must be positive number. Therefore D cannot be true.



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Re: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
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27 Feb 2019, 03:09
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Re: If x^3.5 > y^2.5 > z^1.5, then which of the following cannot be true?
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