Question

Manish bought 1000 pencils for rs 3000 and sold 200 of these at a gain of 5% at what gain percentage he must sell the remaining pencil so as to gain 15% in whole transaction

Answer 1

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Given, cost of 1000 pencils = Rs 3000
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cost of 1 pencil = 3000 /1000 = Rs 3

since , he sold 200 pencils at 5% gain

so then ,
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Find cost price of 200 pencils :
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cost price = 200×3 = Rs 600

remaining pencils = 1000 -200 = 800 pencils
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Find cost price of remaining pencils :
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cost price = 800×3= Rs 2400

given, gain = 5 % on 200 pencils

selling price of 200 pencils

=cost price of 200 pencils + gain

=Rs 600 + 5% of 600 = Rs 630
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Required gain to be 15% on the whole transaction :
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so then required selling price to be

=3000 + 15% of 3000

= 3000 + 15 / 100 × 3000

=3,000 + 450 = Rs 3,450
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selling price of remaining pencils must be :
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=total required selling price - selling price of sold pencils

3450 - 630 = Rs 2820

gain = selling price - cost price

= 2820 - 2400= Rs 420

gain % = gain / cost price × 100

= 420 / 2400 × 100 = 420 / 24 = 17.5 %

therefore , he should sell remaining pencils at a profit (gain) of 17.5% to gain 15 % on the whole transaction.

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Your Answer : 17.5 %
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Answer 2

C.P of 1000 pencils=Rs.3000

C.P of one pencil= 3000/1000 =Rs.3

Manish sold 200 pencils at the gain of 5%

C.P of 200 pencils= 3(200) =Rs.600

Profit= 5% of CP of 200 pencils= 5*600/100 = Rs.30

S.P of 200 pencils= C.P of 200 pencils + Profit = 600+30 =Rs.630

Manish wants to make a profit of 15% of whole transaction

Profit of whole transaction= 15*3000/100 =Rs.45

Profit to be made for 2nd transaction

= Profit of whole transaction - Profit of 1st transaction

= 450-30

= Rs.420

C.P of remaining pencils= 800*3 =Rs.2400

Let 'x' be the profit percentage of 2nd transaction

Profit of 2nd transaction= C.P of remaining pencils * (x/100)

=> 420 = 2400x/100

=> 420 = 24x

=> x = 420/24

=> x = 17.5

Answer is 17.5

Hope it helps