All Exams Test series for 1 year @ ₹349 only
Question

If $\frac{x}{y} = \left(-\frac{1}{3}\right)^{-3} \div \left(\frac{2}{3}\right)^{-4}$, then the value of $\left(\frac{x}{y} + \frac{y}{x}\right)^{-1} \times \left(\frac{y}{x}\right)^{-1}$ is:

The correct answer is
$\frac{165}{48}$

Algebra Exponent Problem Analysis

This problem requires us to calculate the value of a specific algebraic expression involving fractions and exponents. We are given the ratio $\frac{x}{y}$ and need to find the value of $\left(\frac{x}{y} + \frac{y}{x}\right)^{-1} \times \left(\frac{y}{x}\right)^{-1}$.

Ratio Calculation $\frac{x}{y}$

First, let's determine the value of $\frac{x}{y}$ using the provided information:

$$ \frac{x}{y} = \left(-\frac{1}{3}\right)^{-3} \div \left(\frac{2}{3}\right)^{-4} $$

We will evaluate each part of this expression:

  • Evaluating $\left(-\frac{1}{3}\right)^{-3}$: Recall the rule for negative exponents: $ \left(\frac{a}{b}\right)^{-n} = \left(\frac{b}{a}\right)^{n} $. $$ \left(-\frac{1}{3}\right)^{-3} = \left(\frac{-1}{3}\right)^{-3} = \left(\frac{3}{-1}\right)^{3} = (-3)^3 = -27 $$
  • Evaluating $\left(\frac{2}{3}\right)^{-4}$: Using the same rule for negative exponents: $$ \left(\frac{2}{3}\right)^{-4} = \left(\frac{3}{2}\right)^{4} = \frac{3^4}{2^4} = \frac{81}{16} $$
  • Performing the division to find $\frac{x}{y}$: Now, we divide the result of the first term by the result of the second term: $$ \frac{x}{y} = -27 \div \frac{81}{16} $$ Dividing by a fraction is the same as multiplying by its reciprocal: $$ \frac{x}{y} = -27 \times \frac{16}{81} $$ We can simplify this calculation. Since $81 = 3 \times 27$, we get: $$ \frac{x}{y} = -\frac{27 \times 16}{81} = -\frac{1 \times 16}{3} = -\frac{16}{3} $$

So, the ratio $\frac{x}{y}$ is equal to $-\frac{16}{3}$.

Reciprocal Ratio $\frac{y}{x}$

The term $\frac{y}{x}$ is the reciprocal of $\frac{x}{y}$.

$$ \frac{y}{x} = \frac{1}{\frac{x}{y}} = \frac{1}{-\frac{16}{3}} = -\frac{3}{16} $$

Target Expression Evaluation

Now we substitute the values of $\frac{x}{y}$ and $\frac{y}{x}$ into the expression $\left(\frac{x}{y} + \frac{y}{x}\right)^{-1} \times \left(\frac{y}{x}\right)^{-1}$.

Step 1: Calculate $\left(\frac{x}{y} + \frac{y}{x}\right)^{-1}$

  • First, find the sum $\frac{x}{y} + \frac{y}{x}$: $$ \frac{x}{y} + \frac{y}{x} = -\frac{16}{3} + \left(-\frac{3}{16}\right) = -\frac{16}{3} - \frac{3}{16} $$
  • To add these fractions, we find a common denominator, which is $3 \times 16 = 48$: $$ -\frac{16 \times 16}{48} - \frac{3 \times 3}{48} = \frac{-256}{48} - \frac{9}{48} = \frac{-256 - 9}{48} = -\frac{265}{48} $$
  • Next, we find the inverse of this sum: $$ \left(\frac{x}{y} + \frac{y}{x}\right)^{-1} = \left(-\frac{265}{48}\right)^{-1} = -\frac{48}{265} $$

Step 2: Calculate $\left(\frac{y}{x}\right)^{-1}$

  • Using the value $\frac{y}{x} = -\frac{3}{16}$, we find its inverse: $$ \left(\frac{y}{x}\right)^{-1} = \left(-\frac{3}{16}\right)^{-1} = -\frac{16}{3} $$

Step 3: Multiply the results from Step 1 and Step 2

  • Finally, multiply the two results obtained: $$ \left(-\frac{48}{265}\right) \times \left(-\frac{16}{3}\right) $$
  • The product of two negative numbers is positive: $$ \frac{48}{265} \times \frac{16}{3} $$
  • Simplify the expression. We notice that $48$ is divisible by $3$ ($48 \div 3 = 16$): $$ \frac{16 \times 16}{265} = \frac{256}{265} $$

The calculated value of the expression is $\frac{256}{265}$.

Answer Verification and Options

Our detailed calculation shows that the value of the expression $\left(\frac{x}{y} + \frac{y}{x}\right)^{-1} \times \left(\frac{y}{x}\right)^{-1}$ is $\frac{256}{265}$.

The options provided are:

  • Option 1: $\frac{165}{48}$
  • Option 2: $\frac{155}{3}$
  • Option 3: $\frac{145}{9}$
  • Option 4: $\frac{265}{9}$

The correct answer text provided is $\frac{165}{48}$, which corresponds to Option 1. Please note that our derived result $\frac{256}{265}$ does not match any of the given options or the indicated correct answer. The steps shown above represent the accurate mathematical procedure for solving the problem as stated.

Was this answer helpful?

Important Questions from Surds and Indices

  1. The value of (0.3) [{(200 - 146)/(3 × 3 × 3)} - 3] is:

  2. The expression \(\frac{{15\left( {\sqrt {10} + \sqrt 5 } \right)}}{{\sqrt {10\;} + \sqrt {20} + \sqrt {40} - \sqrt 5 - \sqrt {80} }}\)  is equal to:

  3. Let \(x = \left( {\frac{{√ {1875} }}{{√ {3888} }} \div \frac{{√ {1200} }}{{\sqrt 768}}} \right) \times \frac{{√ {175} }}{{√ {1792} }}\) . Then √x is equal to:

  4. If \(x = \sqrt {-\sqrt 3 + \sqrt {3 + 8\sqrt {7 + 4\sqrt 3}}}\)  where x > 0, then the value of x is equal to:

  5. What is the value of \(\frac{\sqrt{7}+\sqrt{5}}{\sqrt{7}−\sqrt{5}} \div \frac{\sqrt{14}+\sqrt{10}}{\sqrt{14}−\sqrt{10}}+\frac{\sqrt{10}}{\sqrt{5}}\) ?

Need Expert Advice?

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App