GIVEN:Vyom purchased 30 DOZEN pens at the rate Rs 48 per dozen.He sold 10 dozen at the profit = 20%The remaining 20 at the profit = 10%Formula:SP = CP × (100 + Profit%)/100Profit = SP – CPProfit % = (Profit/CP) × 100Calculation:Total cost price of 30 dozen pens = 30 × 48 = Rs. 1440Total SELLING price of 30 dozen pens ⇒⇒ 10 × 48 × [120/100] + 20 × 48 × [110/100]⇒ 48 × 12 + 96 × 11⇒ 576 + 1056⇒ 1632Profit = 1632 – 1440∴ Profit = 192Profit % = (192/1440) × 100∴ Profit % = 13.33%