Question

A man sold a book at a loss of 20%
If he had sold the book for z12
more, he would have gained 10%
find the cost price of the book.​

Answer 1

$\large\mathbb \pink{\fcolorbox{pink}{black}{ \ SOLUTION \ }}$

$\large\mathbb \purple{\fcolorbox{pink}{black}{ \ GIvEn \ }}$

• SP (Loss %) = 20 %
• If he had sold the book at Rs 12 then he would have gained 10 %.

$\large\mathbb \orange{\fcolorbox{pink}{black}{ \ TO FIND: \ }}$

Cost price of the book = ?

Formula usEd :

• To solve this question you need to know the imp. formulas related to SP and CP !
• ∙ SP= 100100−L% ×CP: SP =100 + G %100
• SP= 100100+G%×CP

$\large\mathbb \red{\fcolorbox{pink}{black}{ \ HERE, \ }}$

• • G% = Gain Percentage

• • L% = Loss Percentage

• • CP = Cost Price

• • SP = Selling Price

Let's proceed to the question now !!

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$\large\mathbb \orange{\fcolorbox{pink}{black}{ \ SOLUTION \ }}$

Let us assume that x be the Cost Price of the book,

According to Selling Price formula ,

• :⟹SP= 100100−L%×CP
• :⟹SP= 100 100−20% ×x

• :⟹SP= 10080×x

• :⟹SP=0.8x

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As it is given that, if he had sold the book at Rs 12 then he would have gained 10 %.

$\large\mathbb \orange{\fcolorbox{pink}{black}{ \ So, \ }}$

• :⟹ 100100+G% ×CP=0.8x+12

• :⟹ 100100+10×x=0.8x+12

• :⟹ 100110×x=0.8x+12

• :⟹1.1×x=0.8x+12

• :⟹12=1.1x−0.8x

• :⟹12=0.3x

• :⟹x= 0.3/12

• :⟹ Rs x=40 ★

$\large\mathbb \red{\fcolorbox{pink}{black}{ \ ANSWER \ }}$

Therefore, the Cost Price(CP) of the book is Rs 40 .

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