#### Answer

{$15$}

#### Work Step by Step

First, we will cross multiply the two sides of the equation to simplify it, and then we will solve the resultant equation:
$\frac{3n-1}{4}=\frac{5n+2}{7}$
$7(3n-1)=4(5n+2)$
$21n-7=20n+8$
$21n-20n=8+7$
$n=15$
Therefore, the solution set is {$15$}.