Question

Question 87

Solve the following:

Find a number whose fifth part increased by 30 is equal to its fourth part decreased by 30.

Answer 1

Let the number be x.
According to the question,
$\frac{x}{5}+30=\frac{x}{4}-30$
$\Rightarrow \frac{x}{5}-\frac{x}{4}=-30-30\Rightarrow \frac{4x-5x}{20}=-60\Rightarrow -x=-60\times 20\therefore x=1200$
Hence, the required number is 1200.