Question

A shipment of 23 television sets contain three defective ones. In how many ways can a vending machine purchase four of these units and receive two good units ?

Answer 1

$\frac{x}{y} \frac{x}{y} \frac{x}{y} \frac{x}{y} \frac{x}{y} \neq \sqrt{x} \sqrt[n]{x}$