tlng d jwb y,jwbnya dng serius.jk tdk srius,sy laporin.

harga awal = Rp. 90.000
potongan harga = Rp. 13.500

% potongan harga = 13.500 / 90.000 x 100%
                              = 3/20 x 100%
                              = 3 x 5%
                              = 15 %

jawaban C