tolong bantu saya mengerjakan tugas saya

[tex]1. \: ali \: = 15n \\ budi \: = 20n \\ dedi \: = 8n \\ \\ 15n \: + 20n + 8n \: = 129 \\ \\ 43n \: = 129 \\ \\ n \: = \frac{129}{43} \\ \\ n = 3 \\ \\ jdi \\ \\ ali \: = 15n \: = 15 \times n \: = 15 \times 3 = 45 \\ \\ budi \: = 20n \: = 20 \times n \: = 20 \times 3 = 60 \\ \\ dedi \: = 8n \: = 8 \times n \: = 8 \times 3 = 24 \\ \\ 45 - 24 \\ \\ 21 \: kelereng \: (c) \\ \\ \\ \\ [/tex]