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Question

If \(X^{y^z}=1, Y^{z^x}=125\)  and  \(Z^{y^x}=243\)  (x, y and z are natural numbers), then what is the value of 9x + 10y - 18z?

This question was previously asked in
SSC CGL 2017 (Tier 1) Previous Year Paper (16-Aug-2017) (Shift 1)
The correct answer is

5

Step 1 — From \(X^{y^z}=1\): since x, y, z are natural, the exponent \(y^z\ge 1\), so \(X=1\).

Step 2 — From \(Y^{z^x}=125=5^3\): take \(Y=5,\ z^x=3\Rightarrow z=3,\ x=1\).

Step 3 — From \(Z^{y^x}=243=3^5\): \(Z=3,\ y^x=5\Rightarrow y=5,\ x=1\). Consistent.

Step 4: \(9(1)+10(5)-18(3)=9+50-54=\textbf{5}\).

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Similar Questions

  1. If \(3x+6y+9z = \dfrac{20}{3}, 6x+9y + 3z = \dfrac{17}{3}\)  and  \(18x+ 27y - z = \dfrac{113}{9}\) , then what is the value of  \(75x+113y \ ?\)

  2. 7p - [3q - {8p - (4q - 10p)}] = ?


Important Questions from Linear Equation in 2 or more Variables

  1. If \(3x+6y+9z = \dfrac{20}{3}, 6x+9y + 3z = \dfrac{17}{3}\)  and  \(18x+ 27y - z = \dfrac{113}{9}\) , then what is the value of  \(75x+113y \ ?\)

  2. If the system of equations 2x - 3y - 3 and -4x + qy - p/2 is inconsistent which of the following cannot be the value of p ?

  3. If \(4x + \dfrac{6}{y}= 15 \) and  \(6x - \dfrac{8}{y} = 14\) , then the value of p in y = px - 2 is :

  4. Simplify: 7x + 3x(x – 4) = ?

    A. 10x + 12

    B. 10x – 12

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