hi
let's call X the orignal price.
to rise a price of T% is to multiply it by 1 +T/100
Now what we know ?
we have according to initial data :
T =20 so increase factor is 1+ 20/100 = 1.2
So : 1.2 X = 890
X = 890 /1.2
X = 741.67
Original price is 741.67 dollars
Lets'check :
20% of 741.67 is : 741.66 *0.2 = 148.33
so : 741.67 +148.33 = 890