GST AMOUNT = (100 + 200 + 300 + 400) x 5% = 50
PST1 AMOUNT = (500 x 5% + 500) x 10% = 53
PST2 AMOUNT = 600 x 5% = 30
(200 x 5%) + 200 = 210
210 x 10% = 21
(30 + 21 + 600) x 20% = 130
PST3 AMOUNT = 700 x 5% = 35
(300 x 5%) + 300 = 315
315 x 10% = 32
(400 x 5%) + 400 = 420
420 x 20% = 84
(35 + 32 + 84 + 700) x 30% = 255
NOTE
: LIMIT PRICE will be applied to the following judgement.
GST: |(100+200+300+400)|>LIMIT PRICE then TAX is calculated.
PST1:|(500x5%+500)|>LIMIT PRICE then TAX is calculated.
PST2:|(600x5%+((200x5%)+200)x10%+600)|>LIMIT PRICE then TAX is
calculated.
PST3:|(700x5%)+((300x5%)+300)x1%+((400x5%)+400)x20%+700|>LIMIT
PRICE then TAX is calculated.