n = 40,000
To find the value of n, you want it to be on one side of the equation, and you want all the numbers to be on the other side. Starting out, this equation reads:
160,000/n = 4.
First, to get n out of the denominator (or bottom of the fraction), multiply both sides by n. On the left side, this will cancel out, leaving only 160,000. On the right side, you will now have 4n. So the equation should read:
160,000 = 4n.
To get n by itself, divide by 4 on both sides, leaving you with 40,000 = n.