The solution is as follows:

**Everything is clear. I am only confused how he solved for "Loop 2:" in his solution**

Below is my attempt kindly advise me of my mistake.

We know that i2 does not equal 0.5*i4. Because 0.5*i4 is a VOLTAGE and not a CURRENT. so, how are they equal?

This is my confusion.

The question and answer are from: FE Exam Review: Electrical and Computer Engineering 1st Edition by Myron E. Sveum Publisher : Professional Publications, Inc. ISBN-10 : 1591260698 ISBN-13 : 978-1591260691