Andi, bani, candra membeli alat tulis di toko buku andi membeli 4 buku tulis, 3 pulpen dengan harga Rp 23,500. bani membeli 3 buku dan 2 pulpen dengan harga Rp

mencari harganya terlebih dahulu
-anggap buku = x
-anggap pulpen = y

Eliminasi y
4x + 3y = 23,500 => dikali 2
3x + 2y = 17,000 => dikali 3
________________

8x + 6y = 47,000
9x + 6y = 51,000
_______________-
-x = -4.000 dikali -1
x = 4,000


diketahui x = 4.000 substitusi ke
3x + 2y = 17.000
3.(4,000) + 2y = 17,000
12,000 + 2y = 17,000
2y = 17,000 - 12,0000
2y = 5,000
y = 2,500



jadi harga 1 buku = 4.000
----- harga 1 pulpen = 2,500

pembuktian
Candra membeli 4buku dan 3 pulpen
=4.(4.000) + 3.(2,500)
= 16,000 + 7,500
= 23,500

Bani membeli 3buku dan 2 pulpen
= 3.(4,000) + 2.(2,500)
= 12,000 + 5,000
= 17,000


Jadi jika candra membeli 2 buku dan 3 pulpen maka:

= 2.(4,000) + 3.(2,500)
= 8,000 + 7,500
= 15,500


maka candra membayar Rp. 15,500


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