Verified Answer :

Okay :)
Well first you need to do the multiplication.
52/5n=405
  So 52=10 and 40 5=200
So now plug those numbers into the equation.
10/5n=200
 Now we divide :) So 10/5=2
So what do we have left over??
2n=200
To find n we are just going to divide both sides by 2 so
200/2=100
So n=100
Hope this helps! If you need anymore help or further explanation jsut let me know!!! :) 

52/5n=405

Lets start by simplifying. 

52/5n=405
5*2/5n = 200  
2n = 200
2n/2 = 200/2  (Divide by 2 on both sides)
n = 100  <<< Final answer

Our answer is n = 100