Tolong bantu dan paki cara ya

harga jual didiskon 20% = harga beli + 20% harga beli
(100% - 20%) harga jual = (100% + 20%) harga beli
80% harga jual = 120% harga beli
harga jual = 120%/80% harga beli .100%
harga jual = 150% harga beli
Jadi, selisih harga jual dan harga beli (dalam persen)
= 150% - 100% = 50% dari harga beli