Hey there!
For this problem and problems like these, it's easier just to draw everything out. Once you get the hang of envisioning these drawings in your mind, you won't have to, but when you're starting out on problems like these, it's best to draw yourself little representations of the situation and label everything accordingly.
I have attached such a diagram. Basically, I calculated 40% of 60 inches, then calculated 75% of 40% of 60 inches. Hope my drawing helps you see the situation a little better.
Keep in mind that in order to multiply a whole number by a percentage, you need to convert it to a decimal. As an example, 40% will be converted to 0.40, or just 0.4.
Hope this helped you out!
