Answer:
Hi im not sure but if I was doing this this is what i would say
Explanation:
a) since the pizza is split in 6th then the pizza would be 6/6th
b) 7/4 is equal to 1 2/4 ( not 100% simplified ) but 1 2/4 also equals to 6/6ths because 1 2/4 = 4+2=6 (not the best accurate explanation )
c) no slices are left over if joan ate 7/4th of the pizza XD