Let's work through part (c) where we need to express the repeating decimal $2.\overline{715}$ as a fraction.

Steps to convert a repeating decimal to a fraction:

Let $x = 2.\overline{715}$, meaning: $x = 2.715715715\ldots$

Step 1: Eliminate the repeating part by multiplying both sides by 1000.

This shifts the decimal point three places: $1000x = 2715.715715715\ldots$

Step 2: Subtract the original $x = 2.715715715\ldots$ from the equation.

$1000x - x = 2715.715715715\ldots - 2.715715715\ldots$ $999x = 2713$

Step 3: Solve for $x$:

$x = \frac{2713}{999}$

Step 4: Simplify the fraction (if possible).

We now check if $\frac{2713}{999}$ can be simplified. However, 2713 and 999 have no common factors, so the fraction is already in its simplest form.

Thus, the repeating decimal $2.\overline{715}$ as a fraction is: $\boxed{\frac{2713}{999}}$

Let me know if you need more details or have any other questions!

Here are five related questions to expand on this:

1. How do you convert a non-repeating decimal to a fraction?
2. What is the general method to convert any repeating decimal to a fraction?
3. Why is it important to simplify fractions?
4. Can repeating decimals always be expressed as fractions?
5. What are some real-world applications of converting repeating decimals to fractions?

Tip: When simplifying fractions, always check for the greatest common divisor (GCD) of the numerator and denominator to ensure the fraction is in its simplest form.