By selling a flower pot for Rs 322, a man gains 15%.

$\mathrm{SP}=\mathrm{Rs} 322$

Gain percentage $=15 \%$

$\therefore \mathrm{CP}=\left\{\frac{100}{(100+\text { gain } \%)} \times \mathrm{SP}\right\}$

$=$ Rs. $\left\{\frac{100}{(100+15)} \times 322\right\}$

$=$ Rs. $\left(\frac{100}{115} \times 322\right)$

$=$ Rs. 280

Now, desired SP $=\left\{\frac{(100+\text { gain } \%)}{100} \times \mathrm{CP}\right\}$

$=$ Rs. $\left\{\frac{(100+20)}{100} \times 280\right\}$

$=$ Rs. $\left(\frac{120}{100} \times 280\right)$

$=$ Rs. 336

∴ The desired selling price is Rs 336.