Description for Correct answer:
Let the CP of book = Rs.x

Then, SP of book = \( \Large \frac{ \left(100+12\right) \times x }{100}=\frac{112x}{100} \)

Now. the printed price = Rs.y

Then, after discount, the SP

= \( \Large \frac{ \left(100-10\right) \times y }{100}=\frac{90y}{100} \)

Since, both SP are same.

Then, \( \Large \frac{112x}{100} = \frac{90y}{100} = \frac{x}{y} = \frac{45}{56} \)

= 45 : 56