Question 364011
60 = 1.2 * 50
The circumference is a linear function of the radius.
The volume increases as the cube of the radius.
--> 1.2 times the circumference = 1.2^3 times the volume
1.2^3 = 1.728
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The volume of the larger melon is 1.728 times the smaller.
It costs 1.5 times as much, so it's cheaper per unit volume.
How much more is seeds and rind is not stated, tho, and "better" is not a well defined parameter.