Step-by-step explanation:
If she is able to achieve her aim, then the robot is very efficient, as it uses as low as 49 joules in filtering 343 litres of air and water.
It will now be a question of what time the robot is able to achieve this feat, if it is able to do it in a time that matches the quality of the work it does, then it will be reasonable to call the robot efficient, and fast too.
