the employee bought it for 172.50, that's with a 25% discount, so 100% - 25% = 75%, so, the employee is only paying 75% of the current price, which is 172.50, let's say "x" is the regular price.
so, if "x" is the 100%, and we know that 172.50 is the 75%, what the dickens is "x"?
[tex]\bf \begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
x&100\\
172.50&75
\end{array}\implies \cfrac{x}{172.50}=\cfrac{100}{75}\implies x=\cfrac{172.50\cdot 100}{75}
\\\\\\
x=230[/tex]
now, we know the 230 is the price, but already increased by 15%, so hmm if say the item before the increase is say "p", which is 100%, and we know that 230 is 100% + 15% = 115%, then what is "p"?
[tex]\bf \begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
230&115\\
p&100
\end{array}\implies \cfrac{230}{p}=\cfrac{115}{100}\implies \cfrac{230\cdot 100}{115}=p[/tex]