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The average price of 10 books is Rs.12 while the average price of 8 of these books is Rs. 11.75. Of the remaining two books, if the price of one book is 60% more than the price of the other, what is the price of each of these two books?
Answer & Solution
Correct Answer:
Option
C
Total cost of 10 books = Rs. 120
Total cost of 8 books = Rs. 94
⇒ The cost of 2 books = Rs. 26
Let the price of each book be x and y.
⇒ x + y = 26 - - - - - -(1)
Given that the price of 1 book is 60% more than the other price
$$\eqalign{ & \left( {\frac{{160}}{{100}}} \right)y + y = 26 \cr & \Rightarrow y\left( {\frac{{160}}{{100}} + 1} \right) = 26 \cr & \Rightarrow y\left( {\frac{{160 + 100}}{{100}}} \right) = 26 \cr & \Rightarrow y = \frac{{\left( {26 \times 100} \right)}}{{260}} \cr & \Rightarrow y = 10 \cr & {\text{Substituting}}\,\,y = 10\,\,{\text{in }}{\kern 1pt} \left(1 \right){\text{we get}}, \cr & x + 10 = 26 \cr & x = 16 \cr} $$
Total cost of 8 books = Rs. 94
⇒ The cost of 2 books = Rs. 26
Let the price of each book be x and y.
⇒ x + y = 26 - - - - - -(1)
Given that the price of 1 book is 60% more than the other price
$$\eqalign{ & \left( {\frac{{160}}{{100}}} \right)y + y = 26 \cr & \Rightarrow y\left( {\frac{{160}}{{100}} + 1} \right) = 26 \cr & \Rightarrow y\left( {\frac{{160 + 100}}{{100}}} \right) = 26 \cr & \Rightarrow y = \frac{{\left( {26 \times 100} \right)}}{{260}} \cr & \Rightarrow y = 10 \cr & {\text{Substituting}}\,\,y = 10\,\,{\text{in }}{\kern 1pt} \left(1 \right){\text{we get}}, \cr & x + 10 = 26 \cr & x = 16 \cr} $$
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