That's not correct. In general, you would have

Assuming

, you have

, so this turns into
Change the percent to a decimal then multiply
.39(71)=27.69
True.
7/12 is greater than 4/12.
Have a wonderful day! :)
I think they should keep it around, even if it might not be the most efficient strategy. After all, what if you need to solve a problem using multiple strategies?