Question 471566
  <pre><font face = "Tohoma" size = 4 color = "indigo"><b> 
Hi,
Let C represent the total cost of the other 10 books: Mean cost of those = C/10
Anat = 3(C/10) = (3/10)C
T cost = (3/10)C + C = (3/10)c + (10/10)C = 13/10 C
the cost of the anatomy textbook was what fraction of the total amount 
he paid for the 11 books?
{{{((3/10)C)/((13/10)C)= highlight(3/13) }}}