2021-I-06

Ans: $\$260$
Let $\$x$ be the cost of the shirt.

The marked price

$\begin{array}{cl}
= & \$(x+80)
\end{array}$

and the selling price

$\begin{array}{cl}
= & (x+80) \times (1-10\%) \\
= & \$(0.9x+72)
\end{array}$

Since the percentage profit is $30\%$, then we have

$\begin{array}{rcl}
x(1+30\%) & = & 0.9x +72 \\
0.4x & = & 72 \\
x & = & 180
\end{array}$

$\therefore$ the cost of the shirt is $\$180$.

Hence, the marked price of the shirt

$\begin{array}{cl}
= & 180 + 80 \\
= & \$260
\end{array}$