Billy is 6 Tommy is 4 and Bobby is 2
Proof: I thought about this through what I think would be logical so I decided to use even numbers. If Billy is as old as Tommy and Bobby together and then 2 years later he will be twice as old as Tommy is now.
Therefore (I did a bit of guess and check) I decided Tommy must be 4 and Bobby must be 2, so Billy will be 6.
Then, 2 years later, Billy will be 8 and 8 is 2 times Tommy's age now.
Billy is 8 years old, Tommy is 5 years old, and Bobby is 3 years old. This is determined based on a system of equations derived from the information given about their ages. By solving these equations step by step, we find the ages of the Johnson brothers.
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Jawaban:| Ciri-ciri | Abiotik | Biotik | Keterangan ||------------------------|----------------------------------|----------------------------------|------------------------------------------------|| Ekosistem Alami | Suhu udara | Flora (tumbuhan) | Ekosistem yang terbentuk secara alami tanpa campur tangan manusia. || | Kelembapan | Fauna (hewan) | Memiliki interaksi kompleks antara komponen biotik dan abiotik. || | Cahaya matahari | Mikroorganisme | Mempertahankan keseimbangan ekologi secara alami. || | Tanah (jenis dan kesuburan) | Interaksi antar spesies | Habitat untuk berbagai spesies yang saling bergantung. || | Air (kualitas dan kuantitas) | | ||------------------------|----------------------------------|----------------------------------|------------------------------------------------|| Ekosistem Buatan | Struktur fisik (waduk, taman) | Tanaman yang ditanam manusia | Ekosistem yang diciptakan atau dimodifikasi oleh manusia. || | Kualitas tanah (buatan) | Ternak atau hewan peliharaan | Memiliki tujuan tertentu seperti pertanian, rekreasi, atau pemeliharaan. || | Pengaturan iklim mikro | Kegiatan manusia (budidaya) | Bergantung pada intervensi manusia untuk keberlanjutan. || | Saluran irigasi | Pembalakan dan pertanian | Interaksi antara komponen sering lebih sederhana dibandingkan ekosistem alami.|| | Sumber daya yang dikendalikan | | |