On selling an article for Rs 48, a shopkeeper loses 20%.

Solution:

(d) Rs 72

$\mathrm{SP}=\mathrm{Rs} 48$

Loss $=20 \%$

Now, $\mathrm{CP}=\frac{100}{100-\text { loss } \%} \times \mathrm{SP}$

$=\operatorname{Rs}\left(\frac{100}{(100-\text { loss } \%)} \times \mathrm{SP}\right)$

$=\operatorname{Rs}\left(\frac{100}{(100-20)} \times 48\right)$

$=\operatorname{Rs}\left(\frac{100}{80} \times 48\right)$

$=\operatorname{Rs} 60$

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

$=\left\{\frac{(100+20)}{100} \times 60\right\}$

$=\operatorname{Rs}\left(\frac{12}{10} \times 60\right)$

$=\operatorname{Rs} 72$