Yen bought one hi-fi system at 25% discount off its original price. She paid a total of $321 for it, which was inclusive of 7% GST on the discounted price. What was the original price of the hi-fi system?
| |
Percent expressed as units |
Percent expressed as % |
Amount |
| Original price |
100 u |
|
? |
| Discount |
- 25 u |
|
|
| Discounted price |
75 u |
100% |
$300 |
| GST |
|
+ 7% |
|
Amount
to pay |
|
107% |
$321 |
Price of the hi-fi system with 7% GST in percent
= 100% + 7%
= 107%
107% of the hi-fi system with 7% GST = 321
1% of the hi-fi system with 7% GST = 321 ÷ 107 = 3
100% of the hi-fi system with 7% GST = 100 x 3 = 300
Price of the hi-fi system 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 hi-fi system without GST = 300
1 u of the hi-fi system without GST = 300 ÷ 75 = 4
100 u of the hi-fi system without GST = 100 x 4 = 400
Original price of the hi-fi system = $400
Answer(s): $400
