Let the original price of the dress be x.
Discount on dress = 15 %
Hence, price discount on the dress
= 15 % of x = [tex] \frac{15}{100} x[/tex] = 0.15x
Hence, sale price after discount = x - 0.15x = 0.85x
We know the sale price is $ 51.
0.85x = 51
x = [tex] \frac{51}{0.85} [/tex] = 60
Hence, the original price of the dress is $ 60 .