Question

By what number must a given number be multiplied to decrease it by 30%?

Answer 1

Let the number be x

It is decreased by $30\%$

New number$=x-\frac{30}{100}x$

$=\frac{70}{100}x=\frac{7}{10}x$

$\therefore$ The given number should be multiplied by $\frac{7}{10}$ to decrease it by $30\%$.