Sunil buys 6 pens for Rs. 10 and sells them at a price of Rs. 6 for 4. What percentage is the loss or gain for Sunil?

Correct option is A

Sunil buys 6 pens for Rs. 10 and sells them at a price of Rs. 6 for 4 pens.

Cost Price (CP) of 6 pens = Rs. 10

Selling Price (SP) for 4 pens = Rs. 6 => SP for 1 pen = Rs. 1.5

So, SP for 6 pens = 1.5 × 6 = 9
Loss = CP - SP = 10 − 9 = 1
​$$\text{Loss \%} = \frac{1}{10} \times 100 = 10\%$$​​