#### Answer

$n=4.1$

#### Work Step by Step

$n+3(n-2)=10.4\longrightarrow$ multiply using the distributive property
$n+3n-6=10.4\longrightarrow$ combine like terms
$4n-6=10.4\longrightarrow$ add 6 to each side
$4n-6+6=10.4+6\longrightarrow$ add
$4n=16.4\longrightarrow$ divide each side by 4
$4n\div4=16.4\div4\longrightarrow$ divide
$n=4.1$
When we plug our solution back into the equation, we find that each side of the equation is equal, making our answer correct.