Olivium bought one massage chair at 25% discount off its original price. She paid a total of $660 for it, which was inclusive of 10% GST on the discounted price. What was the original price of the massage chair?

	Percent expressed as units	Percent expressed as %	Amount
Original price	100 u		?
Discount	- 25 u
Discounted price	75 u	100%	$600
GST		+ 10%
Amount to pay		110%	$660

Price of the massage chair with 10% GST in percent
= 100% + 10%
= 110%

110% of the massage chair with 10% GST = 660
1% of the massage chair with 10% GST = 660 ÷ 110 = 6
100% of the massage chair with 10% GST = 100 x 6 = 600

Price of the massage chair 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 massage chair without GST = 600
1 u of the massage chair without GST = 600 ÷ 75 = 8
100 u of the massage chair without GST = 100 x 8 = 800

Original price of the massage chair = $800

Answer(s): $800