A lady shopkeeper allows her customers 10% discount on the marked price of the goods and still gets a profit of 25%.

Solution:

Given,

MP of the fan $=$ Rs. 1250

Discount $=10 \%$

So, Discount $=10 \%$ of 1250

$=0.10 \times 1250$

$=$ Rs. 125

Since SP $=$ MP $-$ Discount,

$S \mathrm{P}=$ Rs. $(1250-125)$

$=$ Rs. 1125

Now,

$S P$ of the fan $=$ Rs. 1125

Profit $=25 \%$

$\mathrm{CP}=\left[\frac{100}{(100+\text { Profit } \%)} \times \mathrm{SP}\right]$

$=\left[\frac{100}{125}\right] 1125$

$=$ Rs. 900

Thus, the cost price of the fan is Rs. 900 .