Question

A shopkeeper buys 100 pens for Rs.200 and sell 20 of them at a gain of 10%.at what gain percent must he sell the reminder so as to gain 20% in all?

Answer 1

CP of 100 pens = Rs. 200

Gain % = (SP-CP)*100/CP

For a gain of 20% in all Total SP = CP + (CP * Gain%)/100

Therefore Total SP= 200 +(200*20)/100 = 240

CP of 20 pens = 200/100*20 = 40

SP of 20 pens at a gain of 10% = 40 +40 * 10/100 =44

remaining pens = 100 -20= 80
SP required for 80 pens = Total SP - SP of 20 pens = 240-44 =196

CP of 80 pens = 200*80/100 = 160

Required gain % = (196-160)*100/160 = 3600/160 = 22.5%

Therefore he has to sell the balance pens at a gain of 22.5%

Answer 2

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