Let:
Op = Original price
Sp = Sale price
r = Discount
Express the discount percentage as a decimal:
45% = 45/100 = 0.45
The sale price will be given by:
[tex]\begin{gathered} Sp=Op-0.45Op \\ where \\ Op=27 \\ so\colon \\ Sp=27-12.5 \\ Sp=14.85 \end{gathered}[/tex]$14.85