Why do this
lends itself to a systematic approach to trial and
improvement. It could be used to extend learners when mass is being
taught or revised. Alternatively, it could be used as an exercise
in number work. A discussion of the role of the fraction in the
problem might be interesting
What is the most a lemon can weigh?
Do you have to have a multiple of $3$ lemons?
Is there more than one possible answer?
How you know you have all the solutions?
Learners could make a table to show the possible solutions and
those which are not possible.
Suggest listing some possibilities.