Question 4901
Let's say the original price of the car is X
and we know that if we take 20% off the original price, we are only paying 80% of the original price.  Our original price was 100% and (20% + 80% = 100%)

Percentages are expressed in decimals, so 80%=.8
and .8x means 80% of original price

.8x=12590 (80% of the original cost is $12,590)

Divide both sides by .8
x=15737.50

So the originial price of the car was $15,737.50