Answer:
the magnitude of the work done by the two blocks is the same.
Explanation:
The work done by block a on block b is given by:
where Fa is the force exerted by block a on block b, and d is the distance they cover.
The work done by block b on block a is given by:
where Fb is the force exerted by block b on block a, and d is still the distance they cover.
For Newton's third law, the force exerted by block a on block b is equal to the force exerted by block b on block a, therefore
and so