GMAT Problem Solving (PS) | Re: On the number line above, the segment from 0 to 1 has been

I resolved it differently by assuming that the graph does represent right proportion. The smallest distance between fifths and sevenths on the graph is right in the middle, either after 2nd fifth or before 3rd
So it's 3/7 - 2/5 = x
x=15/35- 14/35 = 1/35

or 3/5 - x = 4/7
x = 3/5-4/7= 21/35 - 20/35 = 1/35

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