Aused vaccum cleaner sells for $130, which is a 75% reduction from the original price. what was the original price of the vaccum cleaner?
( show how you got the original price, i was absent the day they taught this and don't know what to do)

We are going back to get its original price. We add something an additional price with the discounted price based on the price rate. We multiply $138 by 75% that is ($130)(0.75) = $97.50. So $97.50 is the additional price. So we add $97.50 + $130 = $227.50

We also express this using an algebra as we shorten our solution above. We equate into
D + Dx = P
D(1 + x) = P
where
P = original price
x = price rate
D = discounted
The factor (1 + x) makes the discounted price to be an original price.
So we plug in
$130(1 + 0.75) = $227.50