Aradio is being discounted by 20%. if the sale price of the radio is $51.44, what was thw original price of the radio?

Let's take the data from the problem:

i = 20% = 0.2

Np = $51.44

Now, we can apply in this equation to solve for the original price (Op):

i = Np / Op

1 - 0.2 = 51.44 / Op

0.8 = 51.44 / Op

51.44 / 0.8 = Op

$64.30 = Op

The original price of the radio was $64.30.

Obs.: 0.2 was subtracted from 1 because it's a discount. If it was a increase, we just need to sum to 1.

Hope it helps.