Question regarding Introduction to Memory problem

Here is the problem in question: https://brilliant.org/practice/storing-data-in-a-computer/?problem=calculus-problem-125641&chapter=introduction-to-memory

Given that the total sequential access speed would be .1s for A and B because they are stored continuously, not fragmented, and the same size total (10MB), why do we factor this into our calculation? Isn't the 7x faster number misleading when the only difference is time cost of overhead * number of files?

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Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$