Let's say you have 100 somethings. If you want to increase that by 38%, it means that you add 38 somethings to your 100 so that in the end you get 138 somethings. In order to get 138 from 100, you multiply by 1.38. Therefore, in order to increase something by 38%, you multiply it by 1.38.

Multiply by **1.38**

Careful distinction as follows:

You have an amount of something which is 100% of that something by definition.

You want to increase that "something" by 38%.

So you want to wind up with 138% of that "something."

So your answer is 100% of "something"+ 38% of "something" which will equal (=) 138% of "something."

Now substitute the value of "something" into the equation and solve it.