Hello Sathish
First of all, the text should read:
You can see there are 4 LSAs, one for each of the prefixes.
…not 4 LSAs for each of the prefixes…
In any case, the purpose of a Type 3 LSA is to provide a “summary” of all of the routes that are found in a particular area and advertise it to another area. In other words, it advertises inter-area routes.
Yes, ideally, you want Type 3 LSAs to summarize all of the routes within an area as best as possible in order to make routing tables and OSPF messages smaller and more efficient. In this particular case, each prefix in Area 1 is represented separately. You can change this behavior and make the advertising more efficient by using the area range command that is shown immediately after in the lesson.
To answer your specific question, yes, each individual prefix that appears in the OSPF database is considered a separate Type 3 LSA.
I hope this has been helpful!
Laz