+183 
+2446 I'm pretty sure that GST stands for Goods and Services Tax. It's a Canadian tax, so the rest of the world may be unfamiliar with such:
Anyway, let's calculate the amount paid for a DVD. To find it, find how much the discount affected the price of the DVD:
| $12.50∗0.45=5.625 | This is how much the discount affected the price. Subtract 5.625 from the original price of the DVD. |
| 12.50−5.625=$6.875 | In the context of money, money is always rounded to the nearest hundredth place, so round this number to that decimal. |
| $6.88 | |
Okay, now we know what the cost of the DVD is after discount is applied to the price. Now, let's add the discount. Normally, you would multiply 6.88 by 5% and then add it to 6.88, but there is actually a faster method that requires one fewer step: Multiply 6.88*1.05. See how that saves a step? Let's try it together:
| $6.88∗1.05=$7.224 | Yet again, round to the nearest hundredth. |
| $7.22 | You are done! This is your final cost for the DVD. |
