Question

If $x * y = \frac{1}{x} + \frac{1}{y}$ for all $x,y \in \mathbb{R} - \{0\}$, then $(5 * 2) * (3 * 5) =$ ?

• A. $\frac{185}{64}$
• B. $\frac{185}{56}$
• C. $\frac{170}{39}$
• D. $\frac{145}{82}$

Hint:

Carefully substitute values in custom operations—don’t treat them as normal multiplication.

Answer 1

The Correct Option is B