Question

By what number should ${\displaystyle \frac{-5}{7}}$ be divided so that the result is ${\displaystyle \frac{-15}{28}}$?

Answer 1

Consider the number as x

${\displaystyle \frac{-5}{7}÷\frac{-15}{28}}$

It can be written as

${\displaystyle \frac{-5}{7}\times \frac{1}{x}=\frac{-15}{28}}$

By further calculation

${\displaystyle \frac{-5}{7x}=\frac{-15}{28}}$

So we get

${\displaystyle x=\frac{5}{7}\times \frac{28}{15}=\frac{4}{3}}$

${\displaystyle x=1\frac{1}{3}}$