Identical pens are bought at 10 for ₹ 80. If these pens are sold at 25% profit; the S.P. per pen is :

1. ₹ 6

2. ₹ 10

3. ₹ 12

4. ₹ 8

C.P. of 10 pens = ₹ 80

C.P. of 1 pen = ₹ $\dfrac{80}{10}$ = ₹ 8

Profit = 25%

$\text{Profit\%} = \dfrac{\text{Profit}}{\text{C.P.}} \times 100\\[1em] \Rightarrow 25 = \dfrac{\text{Profit}}{8} \times 100\\[1em] \Rightarrow \text{Profit} = \dfrac{25 \times 8}{100}\\[1em] = \dfrac{200}{100}\\[1em] = 2$

As we know,

$\text{Profit} = \text{S.P. - C.P.}$

Putting the values, we get

$\Rightarrow 2 = \text{S.P.} - 8\\[1em] \Rightarrow \text{S.P.} = 2 + 8\\[1em] \Rightarrow \text{S.P.} = 10\\[1em]$

Hence,option 2 is the correct option.