Penelope bought one oven at 25% discount off its original price. She paid a total of $648 for it, which was inclusive of 8% GST on the discounted price. What was the original price of the oven?

	Percent expressed as units	Percent expressed as %	Amount
Original price	100 u		?
Discount	- 25 u
Discounted price	75 u	100%	$600
GST		+ 8%
Amount to pay		108%	$648

Price of the oven with 8% GST in percent
= 100% + 8%
= 108%

108% of the oven with 8% GST = 648
1% of the oven with 8% GST = 648 ÷ 108 = 6
100% of the oven with 8% GST = 100 x 6 = 600

Price of the oven at 25% discount in units
= 100 u - 25 u
= 75 u

Discounted price = 100% of the price to pay for before adding GST.

75 u of the oven without GST = 600
1 u of the oven without GST = 600 ÷ 75 = 8
100 u of the oven without GST = 100 x 8 = 800

Original price of the oven = $800

Answer(s): $800