Question

A manufacturer determines that the cost of making a computer component is ​$4.191919. Write the repeating decimal cost as a fraction and as a mixed number.

Answer 1

Let $x=4.191919\ldots$. Then $100x=419.191919\ldots$. So

$100x-x=99x=415$

$\implies x=\dfrac{415}{99}=4+\dfrac{19}{99}$