Answer: 97/112
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How to get this answer:
Midpoint formula: (A+B)/2 = C
A and B are the endpoints with C as the midpoint
A = 7/8
B = 6/7
A+B = 7/8 + 6/7
A+B = 49/56 + 48/56
A+B = (49+48)/56
A+B = 97/56
(A+B)/2 = (97/56) divided by 2
(A+B)/2 = (97/56) times (1/2)
(A+B)/2 = (97*1)/(56*2)
(A+B)/2 = 97/112