I am stuck at a study drill in lp3thw help please!

in lp3thw exercise 16 study drill 3 i don’t know its looks easy but i am not able to figure out i cant move forward leaving it i want know and learn the concept please help me.

You’re supposed to write down the study drills you can’t figure out and come back to them. It is totally alright to not get a study and keep on moving. Usually you figure it out by simply moving forward in the book. So try that.