Which mixed number is greater than 6.78

A:6 2/3

B:6 3/4

C:6 7/9

D:6 4/5

Lets test out all the answers

A. 2/3 is about. 666 so A is not

B. 3/5 is. 75 so B is B also not

C 7/9 is 0.7777 which is still less so C is not

D. 4/5 is about 0.80 and this is more than 0.78 so D is the answer