#### Answer

$10\,mL$

#### Work Step by Step

$c_{conc}=0.0750\,M$
$V_{dil}= 500\,mL$
$c_{dil}=0.00150\,M$
The relationship is
$c_{conc}\times V_{conc}=c_{dil}\times V_{dil}$
$\implies$$ 0.0750\,M\times V_{conc}=0.00150\,M\times500\,mL$
Or $V_{conc}=\frac{0.00150\,M\times500\,mL}{0.0750\,M}=10\,mL$