All Indonesian citizens (WNI) have a birth certificate. All WNI over the age of 17 have an ID card (KTP). Some Jakarta residents are under 17 years old.
Let's break down the logic premises into a document ownership table:
Citizen Group
Has Birth Certificate?
Has ID Card (KTP)?
WNI (General)
Yes (All)
Depends on Age
WNI >17 Years
Yes
Yes
WNI <17 Years
Yes
No
Analysis of Jakarta Residents:
Jakarta Residents are WNI: Therefore, all Jakarta residents must have a Birth Certificate.
Age of Jakarta Residents:
Some are <17 years old (only have a Birth Certificate).
Some are >17 years old (have a Birth Certificate and an ID Card).
Since there are Jakarta residents who are over 17 years old (implied by "Some are under 17", meaning the rest are over or equal to 17), this group must possess both documents.
Therefore, the valid conclusion is that some Jakarta residents have a birth certificate and ID card (KTP).
