Quantity A should be bigger:
A can be rewritten to sqr(3)*2 which is approximately 3.5 (I try to memorize square roots up to 10) while Quantity B is approximately 3.
-->Answer A

A

Here
Qty A

\(\sqrt{75} - \sqrt{27}\)

=\(5\sqrt{3}\) - \(3\sqrt{3}\)
=\(2\sqrt{3}\)
nearly = 3.4 (since \(\sqrt{3}\) = 1.728)

Now for Qty B

\(\sqrt{10}\)
we know 9 is the nearest sq value to 10

so square root of 9 = 3

and so square root of 10 = nearly close to 3

Hence qty A> QTy B.

It will be benefit if we know the square root value atleast till 5

I used a banal way of solving the problem , I used the dreaded calculator got the answer in 50 sec. its A

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