We are given,
The mean and standard deviation of Mathematics are 
The mean and standard deviation of Physics are 
The mean and standard deviation of Chemistry are 
Also, we know that coefficient of variation is,
![\[C.V = \frac{{{\text{ Standard deviation }}}}{{{\text{ Mean }}}} \times 100\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-9a6a78f0f2591a16be33848f66982571_l3.png "Rendered by QuickLaTeX.com")
Now,
C.V in Mathematics
![\[ = \frac{{12}}{{42}} \times 100\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-ab98f0d110ca6b2873dac89f4d4b5ad4_l3.png "Rendered by QuickLaTeX.com")
![\[ = 28.57{\text{ }}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-368c51f65a3a0f6f1dc199a4e4fe7bd4_l3.png "Rendered by QuickLaTeX.com")
C.V in Physics
![\[ = \frac{{15}}{{32}} \times 100\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-347786783a1e34676d1b8d85c07cff6c_l3.png "Rendered by QuickLaTeX.com")
![\[ = 46.87\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-ec4ab4e064be47c06eae52df2f5572be_l3.png "Rendered by QuickLaTeX.com")
C.V in Chemistry
![\[ = \frac{{20}}{{40.9}} \times 100\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-5bd7fbeacac12ef9f427d4ac0bd5cb21_l3.png "Rendered by QuickLaTeX.com")
![\[ = 48.89\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-5a8398888cb20ffbabbde4c4ac6a3dbc_l3.png "Rendered by QuickLaTeX.com")
Therefore, out of the three subjects the highest variability in marks is in Chemistry and the highest variability in marks is in Mathematics.