Start with with original price and find 30% of that price:
30% of 810: (0.30)(810) = 243
Now take that 30% away:
810 - 243 = 567
That's the sale price: $567
Find 30% of the sale price:
30% of 567: (0.30)(567) = 170.10
Now add that 30% on to the sale price:
567 + 1701.0 = 737.10
The final price described is $737.10.
Now we need to relate that final price to the original price:
737.10 ÷ 810 = 0.91
This means that the final price is 91% of the original price.