In this question a vital information has been provided. This information can be used for determining the answer to the question that is asked. It is given that 120% of a certain number is 360 pound. The 100% value of the number needs to be determined.
Let us assume the number to be = x
Then
120x/100 = 360
12x/10 = 360
12x = 360 * 10
12x = 3600
x = 3600/12
= 300
Now we can say that the 100% of the number or the actual number is 300 pounds. I hope the problem is clear to you and you can understand the trick involved in the question.