Find the selling price when:

Solution:

(i) $\mathrm{CP}=$ Rs. 1650

Gain percentage $=4 \%$

$S P=\frac{(100+\text { gain } \%)}{100} \times C P$

$=\frac{(100+4)}{100} \times 1650$

$=\frac{104 \times 1650}{100}$

$=$ Rs. 1716

(ii) CP $=$ Rs. 915

Gain percentage $=6 \frac{2}{3} \%=\frac{20}{3} \%$

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

$=\frac{\left(100+\frac{20}{3}\right)}{100} \times 915$

$=\frac{\left(\frac{(320}{3}\right)}{100} \times 915$

$=\left(\frac{320}{3}\right) \times\left(\frac{1}{100}\right) \times 915$

$=$ Rs. 976

(iii) CP $=$ Rs. 875

Loss percentage $=12 \%$

$\mathrm{SP}=\frac{(100-\text { loss } \%)}{100} \times \mathrm{CP}$

$=\frac{(100-12)}{100} \times 875$

$=\frac{77000}{100}$

$=$ Rs. 770

(iv) $\mathrm{CP}=$ Rs. 645

Loss percentage $=13 \frac{1}{3} \%=\frac{40}{3} \%$

$\mathrm{SP}=\frac{(100-\text { loss } \%)}{100} \times \mathrm{CP}$

$=\frac{\left(100-\frac{40}{3}\right)}{100} \times 645$

$=\frac{\left(\frac{300-40}{3}\right)}{100} \times 645$

$=\left(\frac{260}{3}\right) \times\left(\frac{1}{100}\right) \times 645$

$=$ Rs. 559