A book cost $ 15 in a shop. if it is bought on the internet , it cost 80 % of this amount . how much does the book cost if it is bought on the internet? Share with your friends Share 0 Shruti Tyagi answered this Dear student, Cost Price of book=&15When sold on the internet,Cost=80% of &15=80100 ×&15=810×&15=82×&3=4×&3=&12Thus the cost of a book sold on the internet is &12 Regards 1 View Full Answer