Answer:
<u>$660.</u>
Step-by-step explanation:
So when we apply a discount to a product we multiply the price of the product (let's all is x) for the percentage of the discount (let's apply 90% as the probnlem says) so then we have the following operation:
x ⋅ (1-0.9) = y
Variable y is the price at which you bought the product, it's $66, on this case. Therefore, this is the expression we have:
x ⋅ (1-0.9) = $66
Now, to get the original value of the product (x), we solve the equation for x:
x ⋅ (1-0.9) = $66
x= $66 / (1-0.9)
x= $66 / (0.1)
x= <u>$660</u>
<u>• Why did we multiply by 1-0.9?</u>
This is because we were looking for the 10% of the original price, since it's a 90% discount. A simple way to solve the problem would've been to just divide the price by 0.1 (10%), because that's what remains after you discount 90% of the price.
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A different example would be the following:
<u>What was the original price of a product bought for $48 if it has a 60% discount?</u>
x is original price.
Since a 60% discount was applied, 40% of the price remains at full price. Therefore, we multiply the original price (x) by 40%:
x ⋅ 40%= $48
x= $48 / 40%
x= $48 / 0.4
x= 120
<u>$120 was the original price.</u>
