Answer
$\frac{7875}{10000}\text{ and }\frac{1575}{2000}$
Work Step by Step
Starting with the decimal $0.7875$, we can multiply by the fraction $\frac{10000}{10000}$ to get $$\frac{7875}{10000}.$$ We can then divide this fraction by $\frac{5}{5}$ to get $$\frac{1575}{2000}$$. Both of these work because the fractions by which we multiplied and divided are equivalent to $1$.