Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If $x-y=11$ and $\frac{1}{x}-\frac{1}{y}=\frac{11}{24}$, then what is the value of $x^3-y^3+x^2 y^2 ?$

Options:

1115

1331

1105

1307

Correct Answer:

1115

Explanation:

If x - y  = n

then, $x^3 - y^3$ = n3 + 3 × n × xy

$x-y=11$

$\frac{1}{x}+\frac{1}{y}=\frac{16}{15}$,

Then what is the value of $x^3-y^3+x^2 y^2 ?$

$\frac{1}{x}-\frac{1}{y}=\frac{11}{24}$,

\(\frac{y - x}{xy}\) = $\frac{11}{24}$

\(\frac{-11}{xy}\) = $\frac{11}{24}$

xy = -24

Then, $\left(x^3+y^3\right) $ = 43 - 3 × 4 × $\frac{15}{4}$]

$x^3 - y^3$ = 113 + 3 × 11 × -24 = 539

$x^3-y^3+x^2 y^2 $ = 539 + (-24 × -24) = 1115