Question

The cost price of 18 notebooks is equal to the selling price of 15 notebooks, find the gain percent.​

Answer 1

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Let the cost price of one notebook be Rs 100.

Then , the  cost price of 18 notebooks = 18 x Rs 100 = Rs 1800

Now , the selling price of 15 notebooks= cost price of 18 notebooks

Therefore , the selling price of 15 notebooks= Rs 1800

⇒ The selling price of one notebooks= (Rs 1800) ÷ 15

=120

Now , gain = Selling price- cost price

i.e. gain = 120-100=20

$Gain percent =\dfrac{gain}{cost\ price}\times100</p><p>$

$=\dfrac{20}{100}\times100=20\%$

Hence, the gain percent is 20%.