tolong dibantu?????please

Misalkan :
gantungan kunci = x
pulpen = y
Arya : 24x + 18y = 81.000
Dinda : 20x + 30y = 105.000
________________________
Arya : 120x + 90y = 405.000
Dinda : 120x + 180y = 630.000
_________________________ -
- 90y = - 225.000
y = 2500

24x + 18y = 81.000
24x + 18(2500) = 81.000
24x + 45.000 = 81.000
24x = 81.000 - 45.000
24x = 36.000
x = 1500

Harga gantungan kunci = Rp. 1500
Harga pulpen = Rp. 2500
Jawaban : A