Answer:
(b) 8 32/35
Explanation:
You want the value of the difference 15 5/7 - 6 4/5.
Difference
The difference is ...
15 5/7 -6 4/5 = (15 -6) +(5/7 -4/5) = 9 +((25 -28)/35) = 9 -3/35
= 8 32/35 . . . . choice B
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Additional comment
The sum of two fractions can be computed as ...
a/b +c/d = (ad +bc)/(bd)
Here, that is ...
5/7 -4/5 = (5·5 +7(-4))/(7·5) = (25 -28)/35 = -3/35