Since 9 is a factor of an unknown number, that means that that number has to be a multiple of 9. If 9 is the factor of something then that something HAS to be a multiple of 9.
Why not write all of the numbers in decimal fraction form, to make them easier to compare?
68 2/3 = 68.666...
72 1/2 = 72.500
68 3/10 = 68.300
74 7/11 = 74.636...
68 1/2 = 68.500
550/8 = 68.750
Now ask yourself: Which of the last four numbers is between 68.666.. and 72.500?
Answer:
20
Step-by-step explanation:
170/8.5
I hope it helps you get it right
