# Floor function equation

**Algebra**Level pending

\[ \large \lfloor 5 - \lfloor x \rfloor \rfloor = 15 \]

If all the values of \(x\) that satisfy the equation above are in the interval \(a \le x < b\), find the product \(ab\).

**Note:** \( \lfloor x \rfloor \) is the floor function, or the greatest integer function.