I would suggest a Venn diagram...I will post one in just a second...BUT you Q does not state how many dogs are in the school..... 
Draw the three overlapping circles....
then start where they all overlap 14 have all 3 ribbons
then fill in the 2 circle overlaps with the info given.....
then fill in the big circle portions with the info given.....
add up all of the numbers to find the number of dogs who learned a trick and got at least one ribbon
total 98 dogs
if there is more than 98 dogs in the class, the remainder learned no tricks....