Correct Answer - Option 3 : Rs. 488
Given:
CP of 20 pens = Rs. 400
12 pens sold = 20% profit
8 pens sold = 25% profit
Formula Used:
S.P = C.P × {(100 + profit %)/100}
Where,
S.P = Selling price
C.P = Cost price
Calculation:
According to the question, we have
C.P of 20 pens = Rs. 400
⇒ C.P of 1 pens = Rs. 20
⇒ C.P of 12 = 20 × 12
⇒ 240
and C.P of 8 pens = 20 × 8
⇒ 160
Now,
SP of 12 pens = 240 × (120/100)
⇒ 288
S.P of 8 pens = 160 × (125/100)
⇒ 200
The total S.P = 288 + 200
⇒ 488
∴ The overall selling price of 20 pens is Rs. 488.